8228426: xlc: switch to clang-style warning disabling

Reviewed-by: clanger, mdoerr

make/autoconf/flags-cflags.m4

@@ -229,7 +229,7 @@ AC_DEFUN([FLAGS_SETUP_WARNINGS],
       ;;
 
     xlc)
-      DISABLE_WARNING_PREFIX="-qsuppress="
+      DISABLE_WARNING_PREFIX="-Wno-"
       CFLAGS_WARNINGS_ARE_ERRORS="-qhalt=w"
 
       # Possibly a better subset than "all" is "lan:trx:ret:zea:cmp:ret"

make/hotspot/lib/CompileJvm.gmk

@@ -97,8 +97,7 @@ DISABLED_WARNINGS_solstudio := labelnotused hidef w_novirtualdescr inlafteruse \
     unknownpragma doubunder w_enumnotused w_toomanyenumnotused \
     wvarhidenmem wunreachable wnoretvalue notemsource
 
-DISABLED_WARNINGS_xlc := 1540-0216 1540-0198 1540-1090 1540-1639 1540-1088 \
-    1500-010
+DISABLED_WARNINGS_xlc := tautological-compare shift-negative-value
 
 DISABLED_WARNINGS_microsoft :=
 

make/lib/Awt2dLibraries.gmk

@@ -471,7 +471,6 @@ ifeq ($(call isTargetOs, windows macosx), false)
           $(LIBAWT_HEADLESS_CFLAGS), \
       EXTRA_HEADER_DIRS := $(LIBAWT_HEADLESS_EXTRA_HEADER_DIRS), \
       DISABLED_WARNINGS_gcc := unused-function, \
-      DISABLED_WARNINGS_xlc := 1506-356, \
       DISABLED_WARNINGS_solstudio := E_EMPTY_TRANSLATION_UNIT, \
       LDFLAGS := $(LDFLAGS_JDKLIB) \
           $(call SET_SHARED_LIBRARY_ORIGIN), \
@@ -481,10 +480,6 @@ ifeq ($(call isTargetOs, windows macosx), false)
       LIBS_solaris := $(LIBM) $(LIBDL) $(LIBCXX), \
   ))
 
-  # AIX warning explanation:
-  # 1506-356 : (W) Compilation unit is empty.
-  #            This happens during the headless build
-
   $(BUILD_LIBAWT_HEADLESS): $(BUILD_LIBAWT)
 
   TARGETS += $(BUILD_LIBAWT_HEADLESS)