gdb: put user-supplied CFLAGS at the end

GDB currently doesn't build cleanly with clang (a -Wdeprecated-copy-dtor
error).  I configured my clang-based GDB build with
CXXFLAGS="-Wno-error=deprecated-copy-dtor", so I can use it despite that
problem.  However, I found that it had no effect.  This is because my
-Wno-error=Wdeprecated-copy-dtor switch is followed by -Werror in the
command line, which switches back all warnings to be errors.

If we want the user-supplied C(XX)FLAGS to be able to override flags
added by our configure script, the user-supplied C(XX)FLAGS should
appear after the configure-supplied flags.

This patch moves the user-supplied CXXFLAGS at the very end of the
compilation command line, which fixes the problem described above.  This
means moving it out of INTERNAL_CFLAGS and inlining it in the users of
INTERNAL_CFLAGS.

I observed the problem when building GDB, but the same problem could
happen with GDBserver, so the change is done there too.

In GDBserver, INTERNAL_CFLAGS is passed when linking

gdb/ChangeLog:

	* Makefile.in (COMPILE): Add CXXFLAGS.
	(INTERNAL_CFLAGS_BASE): Remove CXXFLAGS.
	(check-headers): Add CXXFLAGS.

gdbserver/ChangeLog:

	* Makefile.in (COMPILE): Add CXXFLAGS.
	(INTERNAL_CFLAGS_BASE): Remove CXXFLAGS.
	(gdbserver$(EXEEXT)): Add CXXFLAGS.
	(gdbreplay$(EXEEXT)): Add CXXFLAGS.
	($(IPA_LIB)): Add CXXFLAGS.
	(IPAGENT_COMPILE): Add CXXFLAGS.

Change-Id: I00e054506695e0e9536095c6d14827e48abd8f69

gdbserver/Makefile.in

@@ -83,9 +83,12 @@ include $(srcdir)/../gdb/silent-rules.mk
 # GNU make is used.  The overrides implement dependency tracking.
 COMPILE.pre = $(CXX) $(CXX_DIALECT)
 COMPILE.post = -c -o $@
-COMPILE = $(ECHO_CXX) $(COMPILE.pre) $(INTERNAL_CFLAGS) $(COMPILE.post)
 POSTCOMPILE = @true
 
+# CXXFLAGS is at the very end on purpose, so that user-supplied flags can
+# override internal flags.
+COMPILE = $(ECHO_CXX) $(COMPILE.pre) $(INTERNAL_CFLAGS) $(CXXFLAGS) $(COMPILE.post)
+
 # It is also possible that you will need to add -I/usr/include/sys to the
 # CFLAGS section if your system doesn't have fcntl.h in /usr/include (which
 # is where it should be according to Posix).
@@ -158,7 +161,7 @@ PTHREAD_LIBS = @PTHREAD_LIBS@
 WIN32APILIBS = @WIN32APILIBS@
 
 # INTERNAL_CFLAGS is the aggregate of all other *CFLAGS macros.
-INTERNAL_CFLAGS_BASE = ${CXXFLAGS} ${GLOBAL_CFLAGS} \
+INTERNAL_CFLAGS_BASE = ${GLOBAL_CFLAGS} \
 	${PROFILE_CFLAGS} ${INCLUDE_CFLAGS} ${CPPFLAGS} $(PTHREAD_CFLAGS)
 INTERNAL_WARN_CFLAGS = ${INTERNAL_CFLAGS_BASE} $(WARN_CFLAGS)
 INTERNAL_CFLAGS = ${INTERNAL_WARN_CFLAGS} $(WERROR_CFLAGS) -DGDBSERVER
@@ -355,6 +358,7 @@ gdbserver$(EXEEXT): $(sort $(OBS)) ${CDEPS} $(LIBGNU) $(LIBIBERTY) \
 		$(INTL_DEPS) $(GDBSUPPORT)
 	$(SILENCE) rm -f gdbserver$(EXEEXT)
 	$(ECHO_CXXLD) $(CC_LD) $(INTERNAL_CFLAGS) $(INTERNAL_LDFLAGS) \
+		$(CXXFLAGS) \
 		-o gdbserver$(EXEEXT) $(OBS) $(GDBSUPPORT) $(LIBGNU) \
 		$(LIBIBERTY) $(INTL) $(GDBSERVER_LIBS) $(XM_CLIBS) \
 		$(WIN32APILIBS)
@@ -363,6 +367,7 @@ gdbreplay$(EXEEXT): $(sort $(GDBREPLAY_OBS)) $(LIBGNU) $(LIBIBERTY) \
 		$(INTL_DEPS) $(GDBSUPPORT)
 	$(SILENCE) rm -f gdbreplay$(EXEEXT)
 	$(ECHO_CXXLD) $(CC_LD) $(INTERNAL_CFLAGS) $(INTERNAL_LDFLAGS) \
+		$(CXXFLAGS) \
 		-o gdbreplay$(EXEEXT) $(GDBREPLAY_OBS) $(XM_CLIBS) \
 		$(GDBSUPPORT) $(LIBGNU) $(LIBIBERTY) $(INTL) \
 		$(WIN32APILIBS)
@@ -390,6 +395,7 @@ $(IPA_LIB): $(sort $(IPA_OBJS)) ${CDEPS}
 	$(SILENCE) rm -f $(IPA_LIB)
 	$(ECHO_CXXLD) $(CC_LD) -shared -fPIC -Wl,--soname=$(IPA_LIB) \
 		-Wl,--no-undefined $(INTERNAL_CFLAGS) $(INTERNAL_LDFLAGS) \
+		 $(CXXFLAGS) \
 		-o $(IPA_LIB) ${IPA_OBJS} -ldl -pthread
 
 # Put the proper machine-specific files first, so M-. on a machine
@@ -485,7 +491,9 @@ IPAGENT_CFLAGS = $(INTERNAL_CFLAGS) $(UST_CFLAGS) \
 	-fPIC -DIN_PROCESS_AGENT \
 	-fvisibility=hidden
 
-IPAGENT_COMPILE = $(ECHO_CXX) $(COMPILE.pre) $(IPAGENT_CFLAGS) $(COMPILE.post)
+# CXXFLAGS is at the very end on purpose, so that user-supplied flags can
+# override internal flags.
+IPAGENT_COMPILE = $(ECHO_CXX) $(COMPILE.pre) $(IPAGENT_CFLAGS) $(CXXFLAGS) $(COMPILE.post)
 
 # Rules for special cases.