Setup TARGET_C_PREINCLUDE for VxWorks

This patch modifies the C & C++ VxWorks compiler to predefine
the __STDC_ macros verified by gcc.dg/c99-predef-1.c in the testsuite.

2019-12-13  Joel Brobecker  <brobecker@adacore.com>

	* config.gcc <*-*-vxworks*>: Add vxworks-c.o to c_target_objs
	and cxx_target_objs. Set target_has_targetcm to "yes". Add
	vxworks-predef.h to extra_headers.
	* config/t-vxworks (vxworks-c.o): New target.
	* config/vxworks-c.c: New file.
	* config/vxworks/vxworks-predef.h: New file.

From-SVN: r279781

gcc/ChangeLog

+2019-12-30  Joel Brobecker  <brobecker@adacore.com>
+
+	* config.gcc <*-*-vxworks*>: Add vxworks-c.o to c_target_objs
+	and cxx_target_objs. Set target_has_targetcm to "yes". Add
+	vxworks-predef.h to extra_headers.
+	* config/t-vxworks (vxworks-c.o): New target.
+	* config/vxworks-c.c: New file.
+	* config/vxworks/vxworks-predef.h: New file.
+
 2019-12-30  Alexandre Oliva  <oliva@adacore.com>
             Olivier Hainque  <hainque@adacore.com>
 

gcc/config.gcc

@@ -955,6 +955,10 @@ case ${target} in
   xm_defines=POSIX
   extra_options="${extra_options} vxworks.opt"
   extra_objs="$extra_objs vxworks.o"
+  c_target_objs="${c_target_objs} vxworks-c.o"
+  cxx_target_objs="${cxx_target_objs} vxworks-c.o"
+  extra_headers="${extra_headers} ../vxworks/vxworks-predef.h"
+  target_has_targetcm="yes"
   use_gcc_stdint=provide
   tm_file="${tm_file} vxworks-stdint.h"
   case ${enable_threads} in

gcc/config/t-vxworks

@@ -20,6 +20,10 @@ vxworks.o: $(srcdir)/config/vxworks.c $(CONFIG_H) $(SYSTEM_H) coretypes.h \
 	$(TARGET_H) output.h $(TM_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) $<
 
+vxworks-c.o: $(srcdir)/config/vxworks-c.c
+	$(COMPILE) $<
+	$(POSTCOMPILE)
+
 # Both the kernel and RTP headers provide limits.h.  They embed VxWorks
 # specificities and are dated on some configurations so we both need to
 # provide our own version and make sure the system one gets exposed.