diff --git a/make/Bundles.gmk b/make/Bundles.gmk
index 176e80782e8..6dc3a6aa615 100644
--- a/make/Bundles.gmk
+++ b/make/Bundles.gmk
@@ -40,7 +40,7 @@ ifeq ($(OPENJDK_BUILD_OS), windows)
 endif
 
 # Hook to include the corresponding custom file, if present.
-$(eval $(call IncludeCustomExtension, , Bundles-pre.gmk))
+$(eval $(call IncludeCustomExtension, Bundles-pre.gmk))
 ################################################################################
 # BUNDLE : Name of bundle to create
 # FILES : Files in BASE_DIRS to add to bundle
@@ -322,7 +322,7 @@ endif
 ################################################################################
 
 # Hook to include the corresponding custom file, if present.
-$(eval $(call IncludeCustomExtension, , Bundles.gmk))
+$(eval $(call IncludeCustomExtension, Bundles.gmk))
 
 ################################################################################
 
diff --git a/make/CompileDemos.gmk b/make/CompileDemos.gmk
index 0892f05df86..ded03581fc1 100644
--- a/make/CompileDemos.gmk
+++ b/make/CompileDemos.gmk
@@ -303,7 +303,7 @@ endif
 
 ################################################################################
 # Hook to include the corresponding custom file, if present.
-$(eval $(call IncludeCustomExtension, , CompileDemos.gmk))
+$(eval $(call IncludeCustomExtension, CompileDemos.gmk))
 
 all: $(TARGETS)
 images: $(IMAGES_TARGETS)
diff --git a/make/CompileJavaModules.gmk b/make/CompileJavaModules.gmk
index 327d139849f..3c31fce7bcd 100644
--- a/make/CompileJavaModules.gmk
+++ b/make/CompileJavaModules.gmk
@@ -33,7 +33,7 @@ include JavaCompilation.gmk
 include SetupJavaCompilers.gmk
 
 # Hook to include the corresponding custom file, if present.
-$(eval $(call IncludeCustomExtension, , CompileJavaModules.gmk))
+$(eval $(call IncludeCustomExtension, CompileJavaModules.gmk))
 
 ################################################################################
 # Module specific build settings
@@ -689,7 +689,7 @@ endif
 
 ################################################################################
 
-$(eval $(call IncludeCustomExtension, , CompileJavaModules-post.gmk))
+$(eval $(call IncludeCustomExtension, CompileJavaModules-post.gmk))
 
 ################################################################################
 
diff --git a/make/CompileToolsHotspot.gmk b/make/CompileToolsHotspot.gmk
index 48ac77afde5..87d8bd5b3fc 100644
--- a/make/CompileToolsHotspot.gmk
+++ b/make/CompileToolsHotspot.gmk
@@ -35,7 +35,7 @@ include SetupJavaCompilers.gmk
 TARGETS :=
 
 # Hook to include the corresponding custom file, if present.
-$(eval $(call IncludeCustomExtension, , hotspot/CompileTools.gmk))
+$(eval $(call IncludeCustomExtension, hotspot/CompileTools.gmk))
 
 ifeq ($(INCLUDE_GRAAL), true)
   VM_CI_SRC_DIR := $(TOPDIR)/src/jdk.internal.vm.ci/share/classes
diff --git a/make/CompileToolsJdk.gmk b/make/CompileToolsJdk.gmk
index e52a5eba600..78df6a68de8 100644
--- a/make/CompileToolsJdk.gmk
+++ b/make/CompileToolsJdk.gmk
@@ -32,7 +32,7 @@ include SetupJavaCompilers.gmk
 
 ################################################################################
 
-$(eval $(call IncludeCustomExtension, , CompileTools.gmk))
+$(eval $(call IncludeCustomExtension, CompileTools.gmk))
 
 ################################################################################
 
diff --git a/make/Docs.gmk b/make/Docs.gmk
index 7b5bfcc9b76..eb40cfe1a19 100644
--- a/make/Docs.gmk
+++ b/make/Docs.gmk
@@ -37,7 +37,7 @@ $(eval $(call ReadImportMetaData))
 
 ################################################################################
 # Hook to include the corresponding custom file, if present.
-$(eval $(call IncludeCustomExtension, , Docs.gmk))
+$(eval $(call IncludeCustomExtension, Docs.gmk))
 
 ################################################################################
 # This file generates all documentation for OpenJDK.
diff --git a/make/Images.gmk b/make/Images.gmk
index 897d34f4e96..f6a740ecabf 100644
--- a/make/Images.gmk
+++ b/make/Images.gmk
@@ -34,7 +34,7 @@ JDK_TARGETS :=
 JRE_TARGETS :=
 
 # Hook to include the corresponding custom file, if present.
-$(eval $(call IncludeCustomExtension, , Images-pre.gmk))
+$(eval $(call IncludeCustomExtension, Images-pre.gmk))
 
 ############################################################################
 
@@ -426,7 +426,7 @@ $(call SetupCopyDebuginfo,JRE)
 
 # Include custom post hook here to make it possible to augment the target lists
 # before actual target prerequisites are declared.
-$(eval $(call IncludeCustomExtension, , Images-post.gmk))
+$(eval $(call IncludeCustomExtension, Images-post.gmk))
 
 ################################################################################
 
diff --git a/make/Jprt.gmk b/make/Jprt.gmk
index 2370051f39c..f2058029504 100644
--- a/make/Jprt.gmk
+++ b/make/Jprt.gmk
@@ -104,4 +104,4 @@ ALL_TARGETS += jprt_bundle
 
 ################################################################################
 
-$(eval $(call IncludeCustomExtension, , Jprt.gmk))
+$(eval $(call IncludeCustomExtension, Jprt.gmk))
diff --git a/make/Main.gmk b/make/Main.gmk
index fd4ec0949cf..e7a67d896bd 100644
--- a/make/Main.gmk
+++ b/make/Main.gmk
@@ -51,7 +51,7 @@ include $(TOPDIR)/make/common/FindTests.gmk
 ALL_TARGETS :=
 
 # Hook to include the corresponding custom file, if present.
-$(eval $(call IncludeCustomExtension, , Main.gmk))
+$(eval $(call IncludeCustomExtension, Main.gmk))
 
 # All modules for the current target platform.
 ALL_MODULES := $(call FindAllModules)
diff --git a/make/ReleaseFile.gmk b/make/ReleaseFile.gmk
index f902c063dec..00677030fab 100644
--- a/make/ReleaseFile.gmk
+++ b/make/ReleaseFile.gmk
@@ -80,7 +80,7 @@ TARGETS += $(BASE_RELEASE_FILE)
 
 ################################################################################
 
-$(eval $(call IncludeCustomExtension, , ReleaseFile.gmk))
+$(eval $(call IncludeCustomExtension, ReleaseFile.gmk))
 
 ################################################################################
 
diff --git a/make/RunTests.gmk b/make/RunTests.gmk
index 3b3975812b3..d813138f280 100644
--- a/make/RunTests.gmk
+++ b/make/RunTests.gmk
@@ -36,7 +36,7 @@ include FindTests.gmk
 JTREG_TEST_TOPDIRS := $(TOPDIR) $(JTREG_TESTROOTS)
 
 # Hook to include the corresponding custom file, if present.
-$(eval $(call IncludeCustomExtension, , RunTests.gmk))
+$(eval $(call IncludeCustomExtension, RunTests.gmk))
 
 TEST_RESULTS_DIR := $(OUTPUTDIR)/test-results
 TEST_SUPPORT_DIR := $(OUTPUTDIR)/test-support
diff --git a/make/SourceRevision.gmk b/make/SourceRevision.gmk
index f4987cf4679..10dd943d8b1 100644
--- a/make/SourceRevision.gmk
+++ b/make/SourceRevision.gmk
@@ -28,7 +28,7 @@ default: all
 include $(SPEC)
 include MakeBase.gmk
 
-$(eval $(call IncludeCustomExtension, , SourceRevision.gmk))
+$(eval $(call IncludeCustomExtension, SourceRevision.gmk))
 
 ################################################################################
 # Keep track of what source revision is used to create the build, by creating
diff --git a/make/ToolsJdk.gmk b/make/ToolsJdk.gmk
index 34be124a0b6..4ac54f26197 100644
--- a/make/ToolsJdk.gmk
+++ b/make/ToolsJdk.gmk
@@ -29,7 +29,7 @@ _TOOLS_GMK := 1
 include JavaCompilation.gmk
 
 # Hook to include the corresponding custom file, if present.
-$(eval $(call IncludeCustomExtension, , Tools.gmk))
+$(eval $(call IncludeCustomExtension, Tools.gmk))
 
 ################################################################################
 # To avoid reevaluating the compilation setup for the tools each time this file
diff --git a/make/UpdateBuildDocs.gmk b/make/UpdateBuildDocs.gmk
index fe048999b0b..51f7a6588c5 100644
--- a/make/UpdateBuildDocs.gmk
+++ b/make/UpdateBuildDocs.gmk
@@ -63,7 +63,7 @@ TARGETS += $(testing)
 
 ################################################################################
 
-$(eval $(call IncludeCustomExtension, , UpdateBuildDocs.gmk))
+$(eval $(call IncludeCustomExtension, UpdateBuildDocs.gmk))
 
 ################################################################################
 
diff --git a/make/ZipSource.gmk b/make/ZipSource.gmk
index 1e998c8f756..9b03ed98cd5 100644
--- a/make/ZipSource.gmk
+++ b/make/ZipSource.gmk
@@ -33,7 +33,7 @@ include Modules.gmk
 SRC_ZIP_WORK_DIR := $(SUPPORT_OUTPUTDIR)/src
 
 # Hook to include the corresponding custom file, if present.
-$(eval $(call IncludeCustomExtension, , ZipSource.gmk))
+$(eval $(call IncludeCustomExtension, ZipSource.gmk))
 
 ################################################################################
 # Create the directory structure for src.zip using symlinks.
diff --git a/make/autoconf/spec.gmk.in b/make/autoconf/spec.gmk.in
index 84babe101d4..a4b5b437348 100644
--- a/make/autoconf/spec.gmk.in
+++ b/make/autoconf/spec.gmk.in
@@ -847,9 +847,8 @@ CONFIGURE_CMD := $(TOPDIR)/configure
 # This macro is called to allow inclusion of closed source counterparts.
 # Unless overridden in closed sources, it expands to nothing.
 # Usage: This function is called in an open makefile, with the following
-# arguments:
-# $1 the name of the repo, or empty if the top-level repo.
-# $2 the name of the makefile
+# argument:
+# $1 the name of the makefile
 define IncludeCustomExtension
 endef
 
diff --git a/make/common/FindTests.gmk b/make/common/FindTests.gmk
index ffc711ae9a2..1223638a43c 100644
--- a/make/common/FindTests.gmk
+++ b/make/common/FindTests.gmk
@@ -27,7 +27,7 @@ ifndef _FIND_TESTS_GMK
 _FIND_TESTS_GMK := 1
 
 # Hook to include the corresponding custom file, if present.
-$(eval $(call IncludeCustomExtension, , common/FindTests.gmk))
+$(eval $(call IncludeCustomExtension, common/FindTests.gmk))
 
 # JTREG_TESTROOTS might have been set by a custom extension
 JTREG_TESTROOTS += $(addprefix $(TOPDIR)/test/, hotspot/jtreg jdk langtools nashorn jaxp)
diff --git a/make/common/MakeBase.gmk b/make/common/MakeBase.gmk
index 34e7c032198..582ed7c9854 100644
--- a/make/common/MakeBase.gmk
+++ b/make/common/MakeBase.gmk
@@ -991,6 +991,6 @@ ColonList = \
 ################################################################################
 
 # Hook to include the corresponding custom file, if present.
-$(eval $(call IncludeCustomExtension, , common/MakeBase.gmk))
+$(eval $(call IncludeCustomExtension, common/MakeBase.gmk))
 
 endif # _MAKEBASE_GMK
diff --git a/make/common/Modules.gmk b/make/common/Modules.gmk
index f863310e952..047ad3c8337 100644
--- a/make/common/Modules.gmk
+++ b/make/common/Modules.gmk
@@ -43,7 +43,7 @@ AGGREGATOR_MODULES :=
 DOCS_MODULES :=
 
 # Hook to include the corresponding custom file, if present.
-$(eval $(call IncludeCustomExtension, , common/Modules.gmk))
+$(eval $(call IncludeCustomExtension, common/Modules.gmk))
 
 BOOT_MODULES += \
     java.base \
diff --git a/make/copy/Copy-java.base.gmk b/make/copy/Copy-java.base.gmk
index a6f004ebdf7..affe27ce193 100644
--- a/make/copy/Copy-java.base.gmk
+++ b/make/copy/Copy-java.base.gmk
@@ -25,7 +25,7 @@
 
 include CopyCommon.gmk
 
-$(eval $(call IncludeCustomExtension, , copy/Copy-java.base.gmk))
+$(eval $(call IncludeCustomExtension, copy/Copy-java.base.gmk))
 
 ################################################################################
 #
diff --git a/make/copy/Copy-java.desktop.gmk b/make/copy/Copy-java.desktop.gmk
index a40d65f1e58..b6682e2f29b 100644
--- a/make/copy/Copy-java.desktop.gmk
+++ b/make/copy/Copy-java.desktop.gmk
@@ -25,7 +25,7 @@
 
 include CopyCommon.gmk
 
-$(eval $(call IncludeCustomExtension, , copy/Copy-java.desktop.gmk))
+$(eval $(call IncludeCustomExtension, copy/Copy-java.desktop.gmk))
 
 ################################################################################
 
diff --git a/make/gendata/Gendata-java.base.gmk b/make/gendata/Gendata-java.base.gmk
index a55a3d79af9..67e4776481c 100644
--- a/make/gendata/Gendata-java.base.gmk
+++ b/make/gendata/Gendata-java.base.gmk
@@ -26,7 +26,7 @@
 include GendataCommon.gmk
 
 # Hook to include the corresponding custom file, if present.
-$(eval $(call IncludeCustomExtension, , gendata/Gendata-java.base.gmk))
+$(eval $(call IncludeCustomExtension, gendata/Gendata-java.base.gmk))
 
 include GendataBreakIterator.gmk
 
diff --git a/make/gendata/GendataBlacklistedCerts.gmk b/make/gendata/GendataBlacklistedCerts.gmk
index 0772a797ce4..9eb183ad461 100644
--- a/make/gendata/GendataBlacklistedCerts.gmk
+++ b/make/gendata/GendataBlacklistedCerts.gmk
@@ -23,7 +23,7 @@
 # questions.
 #
 
-$(eval $(call IncludeCustomExtension, , gendata/GendataBlacklistedCerts.gmk))
+$(eval $(call IncludeCustomExtension, gendata/GendataBlacklistedCerts.gmk))
 
 GENDATA_BLACKLISTED_CERTS_SRC += $(TOPDIR)/make/data/blacklistedcertsconverter/blacklisted.certs.pem
 GENDATA_BLACKLISTED_CERTS := $(SUPPORT_OUTPUTDIR)/modules_libs/$(MODULE)/security/blacklisted.certs
diff --git a/make/gendata/GendataFontConfig.gmk b/make/gendata/GendataFontConfig.gmk
index 1031bfba837..52ee37c1880 100644
--- a/make/gendata/GendataFontConfig.gmk
+++ b/make/gendata/GendataFontConfig.gmk
@@ -23,7 +23,7 @@
 # questions.
 #
 
-$(eval $(call IncludeCustomExtension, , gendata/GendataFontConfig.gmk))
+$(eval $(call IncludeCustomExtension, gendata/GendataFontConfig.gmk))
 
 GENDATA_FONT_CONFIG_DST := $(SUPPORT_OUTPUTDIR)/modules_libs/$(MODULE)
 
diff --git a/make/gensrc/Gensrc-java.desktop.gmk b/make/gensrc/Gensrc-java.desktop.gmk
index d28027d991d..f58c4379663 100644
--- a/make/gensrc/Gensrc-java.desktop.gmk
+++ b/make/gensrc/Gensrc-java.desktop.gmk
@@ -26,7 +26,7 @@
 include GensrcCommonJdk.gmk
 
 # Hook to include the corresponding custom file, if present.
-$(eval $(call IncludeCustomExtension, , gensrc/Gensrc-java.desktop.gmk))
+$(eval $(call IncludeCustomExtension, gensrc/Gensrc-java.desktop.gmk))
 
 ifneq ($(OPENJDK_TARGET_OS), windows)
   include GensrcIcons.gmk
diff --git a/make/gensrc/Gensrc-jdk.internal.vm.compiler.gmk b/make/gensrc/Gensrc-jdk.internal.vm.compiler.gmk
index 059437db368..a6cfb3f059e 100644
--- a/make/gensrc/Gensrc-jdk.internal.vm.compiler.gmk
+++ b/make/gensrc/Gensrc-jdk.internal.vm.compiler.gmk
@@ -28,7 +28,7 @@ default: all
 include $(SPEC)
 include MakeBase.gmk
 
-$(eval $(call IncludeCustomExtension, , gensrc/Gensrc-jdk.internal.vm.compiler.gmk))
+$(eval $(call IncludeCustomExtension, gensrc/Gensrc-jdk.internal.vm.compiler.gmk))
 
 GENSRC_DIR := $(SUPPORT_OUTPUTDIR)/gensrc/$(MODULE)
 SRC_DIR := $(TOPDIR)/src/$(MODULE)/share/classes
diff --git a/make/gensrc/Gensrc-jdk.localedata.gmk b/make/gensrc/Gensrc-jdk.localedata.gmk
index 64e1fa9a07b..137ce73e0f6 100644
--- a/make/gensrc/Gensrc-jdk.localedata.gmk
+++ b/make/gensrc/Gensrc-jdk.localedata.gmk
@@ -26,7 +26,7 @@
 include GensrcCommonJdk.gmk
 
 # Hook to include the corresponding custom file, if present.
-$(eval $(call IncludeCustomExtension, , gensrc/Gensrc-jdk.localedata.gmk))
+$(eval $(call IncludeCustomExtension, gensrc/Gensrc-jdk.localedata.gmk))
 
 include GensrcLocaleData.gmk
 include GensrcCLDR.gmk
diff --git a/make/gensrc/GensrcIcons.gmk b/make/gensrc/GensrcIcons.gmk
index 4cefe109840..de04286e62d 100644
--- a/make/gensrc/GensrcIcons.gmk
+++ b/make/gensrc/GensrcIcons.gmk
@@ -23,7 +23,7 @@
 # questions.
 #
 
-$(eval $(call IncludeCustomExtension, , gensrc/GensrcIcons.gmk))
+$(eval $(call IncludeCustomExtension, gensrc/GensrcIcons.gmk))
 
 GENSRC_AWT_ICONS :=
 GENSRC_AWT_ICONS_SRC :=
diff --git a/make/hotspot/gensrc/GenerateSources.gmk b/make/hotspot/gensrc/GenerateSources.gmk
index 4c96e463e63..644bb4f5cb1 100644
--- a/make/hotspot/gensrc/GenerateSources.gmk
+++ b/make/hotspot/gensrc/GenerateSources.gmk
@@ -39,7 +39,7 @@ include gensrc/GensrcAdlc.gmk
 include gensrc/GensrcDtrace.gmk
 include gensrc/GensrcJvmti.gmk
 
-$(eval $(call IncludeCustomExtension, , hotspot/gensrc/GenerateSources.gmk))
+$(eval $(call IncludeCustomExtension, hotspot/gensrc/GenerateSources.gmk))
 
 # While technically the rules below are "gendata" which can be done in parallel
 # with native compilation, let's keep it here for simplicity.
diff --git a/make/hotspot/gensrc/GensrcAdlc.gmk b/make/hotspot/gensrc/GensrcAdlc.gmk
index f6622e88418..c78015e5457 100644
--- a/make/hotspot/gensrc/GensrcAdlc.gmk
+++ b/make/hotspot/gensrc/GensrcAdlc.gmk
@@ -23,7 +23,7 @@
 # questions.
 #
 
-$(eval $(call IncludeCustomExtension, , hotspot/gensrc/GensrcAdlc.gmk))
+$(eval $(call IncludeCustomExtension, hotspot/gensrc/GensrcAdlc.gmk))
 
 ifeq ($(call check-jvm-feature, compiler2), true)
 
diff --git a/make/hotspot/gensrc/GensrcJvmti.gmk b/make/hotspot/gensrc/GensrcJvmti.gmk
index c7340dabc1e..1dfe38fce95 100644
--- a/make/hotspot/gensrc/GensrcJvmti.gmk
+++ b/make/hotspot/gensrc/GensrcJvmti.gmk
@@ -23,7 +23,7 @@
 # questions.
 #
 
-$(eval $(call IncludeCustomExtension, , hotspot/gensrc/GensrcJvmti.gmk))
+$(eval $(call IncludeCustomExtension, hotspot/gensrc/GensrcJvmti.gmk))
 
 ################################################################################
 # Build tools needed for the JVMTI source code generation
diff --git a/make/hotspot/lib/CompileGtest.gmk b/make/hotspot/lib/CompileGtest.gmk
index c944c3481c9..505c6fa5608 100644
--- a/make/hotspot/lib/CompileGtest.gmk
+++ b/make/hotspot/lib/CompileGtest.gmk
@@ -23,7 +23,7 @@
 # questions.
 #
 
-$(eval $(call IncludeCustomExtension, , hotspot/lib/CompileGtest.gmk))
+$(eval $(call IncludeCustomExtension, hotspot/lib/CompileGtest.gmk))
 
 GTEST_TEST_SRC += $(TOPDIR)/test/hotspot/gtest
 GTEST_LAUNCHER_SRC := $(TOPDIR)/test/hotspot/gtest/gtestLauncher.cpp
diff --git a/make/hotspot/lib/CompileJvm.gmk b/make/hotspot/lib/CompileJvm.gmk
index da7d4eafc87..bf4280b8dea 100644
--- a/make/hotspot/lib/CompileJvm.gmk
+++ b/make/hotspot/lib/CompileJvm.gmk
@@ -28,7 +28,7 @@
 include lib/JvmFeatures.gmk
 include lib/JvmOverrideFiles.gmk
 
-$(eval $(call IncludeCustomExtension, , hotspot/lib/CompileJvm.gmk))
+$(eval $(call IncludeCustomExtension, hotspot/lib/CompileJvm.gmk))
 
 ################################################################################
 # Setup compilation of the main Hotspot native library (libjvm).
diff --git a/make/hotspot/lib/JvmFeatures.gmk b/make/hotspot/lib/JvmFeatures.gmk
index 3880e685fe3..9a69c5330bf 100644
--- a/make/hotspot/lib/JvmFeatures.gmk
+++ b/make/hotspot/lib/JvmFeatures.gmk
@@ -23,7 +23,7 @@
 # questions.
 #
 
-$(eval $(call IncludeCustomExtension, , hotspot/lib/JvmFeatures.gmk))
+$(eval $(call IncludeCustomExtension, hotspot/lib/JvmFeatures.gmk))
 
 ################################################################################
 # Setup CFLAGS and EXCLUDES for the libjvm compilation, depending on which
diff --git a/make/hotspot/lib/JvmMapfile.gmk b/make/hotspot/lib/JvmMapfile.gmk
index aae8d0cf866..81bc880fd4f 100644
--- a/make/hotspot/lib/JvmMapfile.gmk
+++ b/make/hotspot/lib/JvmMapfile.gmk
@@ -23,7 +23,7 @@
 # questions.
 #
 
-$(eval $(call IncludeCustomExtension, , hotspot/lib/JvmMapfile.gmk))
+$(eval $(call IncludeCustomExtension, hotspot/lib/JvmMapfile.gmk))
 
 ################################################################################
 # Combine a list of static symbols
diff --git a/make/hotspot/lib/JvmOverrideFiles.gmk b/make/hotspot/lib/JvmOverrideFiles.gmk
index b8eddbd9df3..b9092001e3b 100644
--- a/make/hotspot/lib/JvmOverrideFiles.gmk
+++ b/make/hotspot/lib/JvmOverrideFiles.gmk
@@ -23,7 +23,7 @@
 # questions.
 #
 
-$(eval $(call IncludeCustomExtension, , hotspot/lib/JvmOverrideFiles.gmk))
+$(eval $(call IncludeCustomExtension, hotspot/lib/JvmOverrideFiles.gmk))
 
 ################################################################################
 # This file contains explicit overrides of CFLAGS and/or precompiled header
diff --git a/make/launcher/Launcher-java.base.gmk b/make/launcher/Launcher-java.base.gmk
index 340072ca486..26b89d54b8b 100644
--- a/make/launcher/Launcher-java.base.gmk
+++ b/make/launcher/Launcher-java.base.gmk
@@ -25,7 +25,7 @@
 
 include LauncherCommon.gmk
 
-$(eval $(call IncludeCustomExtension, , launcher/Launcher-java.base.gmk))
+$(eval $(call IncludeCustomExtension, launcher/Launcher-java.base.gmk))
 
 JAVA_RC_FLAGS += -I $(TOPDIR)/src/java.base/windows/native/common
 JAVA_RC_FLAGS += -I $(TOPDIR)/src/java.base/windows/native/launcher/icons
diff --git a/make/launcher/Launcher-java.desktop.gmk b/make/launcher/Launcher-java.desktop.gmk
index ab60dea9b0a..d2e39b440b2 100644
--- a/make/launcher/Launcher-java.desktop.gmk
+++ b/make/launcher/Launcher-java.desktop.gmk
@@ -26,7 +26,7 @@
 include LauncherCommon.gmk
 
 # Hook to include the corresponding custom file, if present.
-$(eval $(call IncludeCustomExtension, , launcher/Launcher-java.desktop.gmk))
+$(eval $(call IncludeCustomExtension, launcher/Launcher-java.desktop.gmk))
 
 ifeq ($(ENABLE_HEADLESS_ONLY), false)
   $(eval $(call SetupBuildLauncher, appletviewer, \
diff --git a/make/lib/Awt2dLibraries.gmk b/make/lib/Awt2dLibraries.gmk
index fcb6ead748a..2fc2d67b06e 100644
--- a/make/lib/Awt2dLibraries.gmk
+++ b/make/lib/Awt2dLibraries.gmk
@@ -23,7 +23,7 @@
 # questions.
 #
 
-$(eval $(call IncludeCustomExtension, , lib/Awt2dLibraries-pre.gmk))
+$(eval $(call IncludeCustomExtension, lib/Awt2dLibraries-pre.gmk))
 
 WIN_AWT_LIB := $(SUPPORT_OUTPUTDIR)/native/$(MODULE)/libawt/awt.lib
 
@@ -1070,4 +1070,4 @@ endif
 ################################################################################
 
 # Hook to include the corresponding custom file, if present.
-$(eval $(call IncludeCustomExtension, , lib/Awt2dLibraries.gmk))
+$(eval $(call IncludeCustomExtension, lib/Awt2dLibraries.gmk))
diff --git a/make/lib/CoreLibraries.gmk b/make/lib/CoreLibraries.gmk
index 6b6f1edacfd..f8e0983a00d 100644
--- a/make/lib/CoreLibraries.gmk
+++ b/make/lib/CoreLibraries.gmk
@@ -26,7 +26,7 @@
 WIN_VERIFY_LIB := $(SUPPORT_OUTPUTDIR)/native/$(MODULE)/libverify/verify.lib
 
 # Hook to include the corresponding custom file, if present.
-$(eval $(call IncludeCustomExtension, , lib/CoreLibraries.gmk))
+$(eval $(call IncludeCustomExtension, lib/CoreLibraries.gmk))
 
 
 ##########################################################################################
diff --git a/make/lib/Lib-java.instrument.gmk b/make/lib/Lib-java.instrument.gmk
index caee912c307..2fbc6ab2835 100644
--- a/make/lib/Lib-java.instrument.gmk
+++ b/make/lib/Lib-java.instrument.gmk
@@ -26,7 +26,7 @@
 include LibCommon.gmk
 
 # Hook to include the corresponding custom file, if present.
-$(eval $(call IncludeCustomExtension, , lib/Lib-java.instrument.gmk))
+$(eval $(call IncludeCustomExtension, lib/Lib-java.instrument.gmk))
 
 ################################################################################
 
diff --git a/make/lib/Lib-java.management.gmk b/make/lib/Lib-java.management.gmk
index e583ca338cc..6e7edc3b115 100644
--- a/make/lib/Lib-java.management.gmk
+++ b/make/lib/Lib-java.management.gmk
@@ -26,7 +26,7 @@
 include LibCommon.gmk
 
 # Hook to include the corresponding custom file, if present.
-$(eval $(call IncludeCustomExtension, , lib/Lib-java.management.gmk))
+$(eval $(call IncludeCustomExtension, lib/Lib-java.management.gmk))
 
 ################################################################################
 
diff --git a/make/lib/Lib-jdk.hotspot.agent.gmk b/make/lib/Lib-jdk.hotspot.agent.gmk
index bd8cdaa4c29..00dfda0c24e 100644
--- a/make/lib/Lib-jdk.hotspot.agent.gmk
+++ b/make/lib/Lib-jdk.hotspot.agent.gmk
@@ -25,7 +25,7 @@
 
 include NativeCompilation.gmk
 
-$(eval $(call IncludeCustomExtension, , hotspot/lib/Lib-jdk.hotspot.agent.gmk))
+$(eval $(call IncludeCustomExtension, hotspot/lib/Lib-jdk.hotspot.agent.gmk))
 
 ################################################################################
 
diff --git a/make/lib/Lib-jdk.management.gmk b/make/lib/Lib-jdk.management.gmk
index f6f68049ada..b04f5b2ed3a 100644
--- a/make/lib/Lib-jdk.management.gmk
+++ b/make/lib/Lib-jdk.management.gmk
@@ -26,7 +26,7 @@
 include LibCommon.gmk
 
 # Hook to include the corresponding custom file, if present.
-$(eval $(call IncludeCustomExtension, , lib/Lib-jdk.management.gmk))
+$(eval $(call IncludeCustomExtension, lib/Lib-jdk.management.gmk))
 
 ################################################################################
 
diff --git a/make/lib/LibCommon.gmk b/make/lib/LibCommon.gmk
index 112a234eb86..487d882dbf2 100644
--- a/make/lib/LibCommon.gmk
+++ b/make/lib/LibCommon.gmk
@@ -26,7 +26,7 @@
 include NativeCompilation.gmk
 
 # Hook to include the corresponding custom file, if present.
-$(eval $(call IncludeCustomExtension, , lib/LibCommon.gmk))
+$(eval $(call IncludeCustomExtension, lib/LibCommon.gmk))
 
 ################################################################################
 
diff --git a/make/test/JtregNativeHotspot.gmk b/make/test/JtregNativeHotspot.gmk
index 8079292213c..073b422566d 100644
--- a/make/test/JtregNativeHotspot.gmk
+++ b/make/test/JtregNativeHotspot.gmk
@@ -35,7 +35,7 @@ include $(SPEC)
 include MakeBase.gmk
 include TestFilesCompilation.gmk
 
-$(eval $(call IncludeCustomExtension, , hotspot/test/JtregNative.gmk))
+$(eval $(call IncludeCustomExtension, hotspot/test/JtregNative.gmk))
 
 ################################################################################
 # Targets for building the native tests themselves.
diff --git a/make/test/JtregNativeJdk.gmk b/make/test/JtregNativeJdk.gmk
index 548e22fbec4..b4780d3c09e 100644
--- a/make/test/JtregNativeJdk.gmk
+++ b/make/test/JtregNativeJdk.gmk
@@ -35,7 +35,7 @@ include $(SPEC)
 include MakeBase.gmk
 include TestFilesCompilation.gmk
 
-$(eval $(call IncludeCustomExtension, , test/JtregNative.gmk))
+$(eval $(call IncludeCustomExtension, test/JtregNative.gmk))
 
 ################################################################################
 # Targets for building the native tests themselves.