Compiling on AIX with xlc17 which contains the new clang 15 frontend
shows the following warnings.

src/java.desktop/unix/native/common/awt/awt_GraphicsEnv.h:53:12: error: a function declaration without a prototype is deprecated in all versions of C and is treated as a zero-parameter prototype in C2x, conflicting with a previous declaration [-Werror,-Wdeprecated-non-prototype]
extern int XShmQueryExtension();
^
/usr/include/X11/extensions/XShm.h:91:6: note: conflicting prototype is here
Bool XShmQueryExtension(
^



src/java.desktop/unix/native/libawt_xawt/xawt/awt_Taskbar.c:158:11: error: using the result of an assignment as a condition without parentheses [-Werror,-Wparentheses]
if (m = fp_unity_launcher_entry_get_quicklist(entry)) {
~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
solved by adding line
DISABLED_WARNINGS_clang_aix_awt_Taskbar.c := parentheses, \

src/java.desktop/share/native/common/java2d/opengl/OGLPaints.c:581:48: error: format string is not a string literal [-Werror,-Wformat-nonliteral]
snprintf(cycleCode, sizeof(cycleCode), noCycleCode, texCoordCalcCode);
^~~~~~~~~~~



src/java.desktop/share/native/common/java2d/opengl/OGLBufImgOps.c:153:48: error: format string is not a string literal [-Werror,-Wformat-nonliteral]
snprintf(finalSource, sizeof(finalSource), convolveShaderSource,
^~~~~~~~~~~~~~~~~~~~

src/java.desktop/unix/native/libawt_xawt/awt/gtk2_interface.c:1095:41: error: '&&' within '||' [-Werror,-Wlogical-op-parentheses]
if ((synth_state & MOUSE_OVER) != 0 && (synth_state & PRESSED) == 0 ||
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~
src/java.desktop/unix/native/libawt_xawt/awt/gtk2_interface.c:1180:29: error: using the result of an assignment as a condition without parentheses [-Werror,-Wparentheses]
if (init_result = (NULL == gtk2_widgets[_GTK_CHECK_MENU_ITEM_TYPE]))
~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
solved by adding line
DISABLED_WARNINGS_clang_aix_gtk2_interface.c := parentheses logical-op-parentheses, \



In harfbuzz, hb-subset.cc we can undo the define for AIX we needed
to compile with xlc16.
In jdk21 we would like to support both compilers, but afterwards
we can omit the define altogether.
See also JDK-8304291: [AIX] Broken build after JDK-8301998