gdb: Respect CXXFLAGS when building with C++ compiler

Currently, even when built with --enable-build-with-cxx, gdb uses
CFLAGS instead of CXXFLAGS.  This commit fixes it.

CXXFLAGS set in the environment when configure was run is now honored
in the generated gdb/Makefile, and you can also override CXXFLAGS in
the command like at make time, with the usual 'make CXXFLAGS="..."'

Objects built with a C compiler (e.g., gnulib) still honor CFLAGS
instead.

gdb/ChangeLog:
2016-01-21  Pedro Alves  <palves@redhat.com>

	* Makefile.in (COMPILER_CFLAGS): New.
	(CXXFLAGS): Get it from configure.
	(INTERNAL_CFLAGS_BASE, INTERNAL_LDFLAGS): Use COMPILER_CFLAGS
	instead of CFLAGS.
	* build-with-cxx.m4 (GDB_AC_BUILD_WITH_CXX): Set and AC_SUBST
	COMPILER_CFLAGS.
	* configure: Regenerate.

gdb/gdbserver/ChangeLog:
2016-01-21  Pedro Alves  <palves@redhat.com>

	* Makefile.in (COMPILER_CFLAGS, CXXFLAGS): New.
	(INTERNAL_CFLAGS_BASE): Use COMPILER_CFLAGS instead of CFLAGS.
	* configure: Regenerate.

7 files changed, 41 insertions, 11 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index a377a322984..68d10ad0acb 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,13 @@
+2016-01-21  Pedro Alves  <palves@redhat.com>
+
+	* Makefile.in (COMPILER_CFLAGS): New.
+	(CXXFLAGS): Get it from configure.
+	(INTERNAL_CFLAGS_BASE, INTERNAL_LDFLAGS): Use COMPILER_CFLAGS
+	instead of CFLAGS.
+	* build-with-cxx.m4 (GDB_AC_BUILD_WITH_CXX): Set and AC_SUBST
+	COMPILER_CFLAGS.
+	* configure: Regenerate.
+
 2016-01-21  Joel Brobecker  <brobecker@adacore.com>
 
 	* location.h (new_address_location): Add new parameters
diff --git a/gdb/Makefile.in b/gdb/Makefile.in
index 895ece68661..5e8eb9aa039 100644
--- a/gdb/Makefile.in
+++ b/gdb/Makefile.in
@@ -81,6 +81,8 @@ CATALOGS = @CATALOGS@
 
 # The name of the compiler to use.
 COMPILER = @COMPILER@
+# Set to CFLAGS or CXXFLAGS, depending on compiler/language.
+COMPILER_CFLAGS = @COMPILER_CFLAGS@
 
 # If you are compiling with GCC, make sure that either 1) You have the
 # fixed include files where GCC can reach them, or 2) You use the
@@ -551,9 +553,10 @@ GLOBAL_CFLAGS = $(MH_CFLAGS)
 
 PROFILE_CFLAGS = @PROFILE_CFLAGS@
 
-# CFLAGS is specifically reserved for setting from the command line
-# when running make.  I.E.  "make CFLAGS=-Wmissing-prototypes".
+# These are specifically reserved for setting from the command line
+# when running make.  I.E.: "make CFLAGS=-Wmissing-prototypes".
 CFLAGS = @CFLAGS@
+CXXFLAGS = @CXXFLAGS@
 
 # Set by configure, for e.g. expat.  Python installations are such that
 # C headers are included using their basename (for example, we #include
@@ -563,14 +566,9 @@ CFLAGS = @CFLAGS@
 # a bit the consequences by putting the Python includes last in the list.
 INTERNAL_CPPFLAGS = @CPPFLAGS@ @GUILE_CPPFLAGS@ @PYTHON_CPPFLAGS@
 
-# Need to pass this to testsuite for "make check".  Probably should be
-# consistent with top-level Makefile.in and gdb/testsuite/Makefile.in
-# so "make check" has the same result no matter where it is run.
-CXXFLAGS = -g -O
-
 # INTERNAL_CFLAGS is the aggregate of all other *CFLAGS macros.
 INTERNAL_CFLAGS_BASE = \
-	$(CFLAGS) $(GLOBAL_CFLAGS) $(PROFILE_CFLAGS) \
+	$(COMPILER_CFLAGS) $(GLOBAL_CFLAGS) $(PROFILE_CFLAGS) \
 	$(GDB_CFLAGS) $(OPCODES_CFLAGS) $(READLINE_CFLAGS) $(ZLIBINC) \
 	$(BFD_CFLAGS) $(INCLUDE_CFLAGS) $(LIBDECNUMBER_CFLAGS) \
 	$(INTL_CFLAGS) $(INCGNU) $(ENABLE_CFLAGS) $(INTERNAL_CPPFLAGS)
@@ -585,7 +583,9 @@ LDFLAGS = @LDFLAGS@
 # I think it's perfectly reasonable for a user to set -pg in CFLAGS
 # and have it work; that's why CFLAGS is here.
 # PROFILE_CFLAGS is _not_ included, however, because we use monstartup.
-INTERNAL_LDFLAGS = $(CFLAGS) $(GLOBAL_CFLAGS) $(MH_LDFLAGS) $(LDFLAGS) $(CONFIG_LDFLAGS)
+INTERNAL_LDFLAGS = \
+	$(COMPILER_CFLAGS) $(GLOBAL_CFLAGS) $(MH_LDFLAGS) \
+	$(LDFLAGS) $(CONFIG_LDFLAGS)
 
 # If your system is missing alloca(), or, more likely, it's there but
 # it doesn't work, then refer to libiberty.
diff --git a/gdb/build-with-cxx.m4 b/gdb/build-with-cxx.m4
index d282092b127..6eb91434791 100644
--- a/gdb/build-with-cxx.m4
+++ b/gdb/build-with-cxx.m4
@@ -33,8 +33,11 @@ AC_DEFUN([GDB_AC_BUILD_WITH_CXX],
 
   if test "$enable_build_with_cxx" = "yes"; then
     COMPILER='$(CXX)'
+    COMPILER_CFLAGS='$(CXXFLAGS)'
    else
     COMPILER='$(CC)'
+    COMPILER_CFLAGS='$(CFLAGS)'
   fi
   AC_SUBST(COMPILER)
+  AC_SUBST(COMPILER_CFLAGS)
 ])
diff --git a/gdb/configure b/gdb/configure
index 701cfcb0239..26a00d8f224 100755
--- a/gdb/configure
+++ b/gdb/configure
@@ -731,6 +731,7 @@ MAKE
 CCDEPMODE
 DEPDIR
 am__leading_dot
+COMPILER_CFLAGS
 COMPILER
 INSTALL_STRIP_PROGRAM
 STRIP
@@ -5015,12 +5016,15 @@ fi
 
   if test "$enable_build_with_cxx" = "yes"; then
     COMPILER='$(CXX)'
+    COMPILER_CFLAGS='$(CXXFLAGS)'
    else
     COMPILER='$(CC)'
+    COMPILER_CFLAGS='$(CFLAGS)'
   fi
 
 
 
+
 # Dependency checking.
 rm -rf .tst 2>/dev/null
 mkdir .tst 2>/dev/null
diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog
index c33c5d33d25..9c42fcf97ff 100644
--- a/gdb/gdbserver/ChangeLog
+++ b/gdb/gdbserver/ChangeLog
@@ -1,3 +1,9 @@
+2016-01-21  Pedro Alves  <palves@redhat.com>
+
+	* Makefile.in (COMPILER_CFLAGS, CXXFLAGS): New.
+	(INTERNAL_CFLAGS_BASE): Use COMPILER_CFLAGS instead of CFLAGS.
+	* configure: Regenerate.
+
 2016-01-21  Yao Qi  <yao.qi@linaro.org>
 
 	* linux-arm-low.c (arm_sigreturn_next_pc): Add parameter
diff --git a/gdb/gdbserver/Makefile.in b/gdb/gdbserver/Makefile.in
index 4719e48576a..f9b9dbe79a3 100644
--- a/gdb/gdbserver/Makefile.in
+++ b/gdb/gdbserver/Makefile.in
@@ -51,6 +51,8 @@ RANLIB = @RANLIB@
 
 # The name of the compiler to use.
 COMPILER = @COMPILER@
+# Set to CFLAGS or CXXFLAGS, depending on compiler/language.
+COMPILER_CFLAGS = @COMPILER_CFLAGS@
 
 CC = @CC@
 CXX = @CXX@
@@ -129,13 +131,14 @@ WERROR_CFLAGS = @WERROR_CFLAGS@
 WARN_CFLAGS_NO_FORMAT = `echo " $(WARN_CFLAGS) " \
 		   | sed "s/ -Wformat-nonliteral / -Wno-format-nonliteral /g"`
 
-# CFLAGS is specifically reserved for setting from the command line
+# These are specifically reserved for setting from the command line
 # when running make.  I.E.  "make CFLAGS=-Wmissing-prototypes".
 CFLAGS = @CFLAGS@
+CXXFLAGS = @CXXFLAGS@
 CPPFLAGS = @CPPFLAGS@
 
 # INTERNAL_CFLAGS is the aggregate of all other *CFLAGS macros.
-INTERNAL_CFLAGS_BASE =  ${CFLAGS} ${GLOBAL_CFLAGS} \
+INTERNAL_CFLAGS_BASE =  ${COMPILER_CFLAGS} ${GLOBAL_CFLAGS} \
 	${PROFILE_CFLAGS} ${INCLUDE_CFLAGS} ${CPPFLAGS}
 INTERNAL_WARN_CFLAGS =  ${INTERNAL_CFLAGS_BASE} $(WARN_CFLAGS)
 INTERNAL_CFLAGS =  ${INTERNAL_WARN_CFLAGS} $(WERROR_CFLAGS) -DGDBSERVER
diff --git a/gdb/gdbserver/configure b/gdb/gdbserver/configure
index 763c77db069..4a6f26badf9 100755
--- a/gdb/gdbserver/configure
+++ b/gdb/gdbserver/configure
@@ -615,6 +615,7 @@ DEPDIR
 am__leading_dot
 host_noncanonical
 target_noncanonical
+COMPILER_CFLAGS
 COMPILER
 RANLIB
 AR
@@ -4834,12 +4835,15 @@ fi
 
   if test "$enable_build_with_cxx" = "yes"; then
     COMPILER='$(CXX)'
+    COMPILER_CFLAGS='$(CXXFLAGS)'
    else
     COMPILER='$(CC)'
+    COMPILER_CFLAGS='$(CFLAGS)'
   fi
 
 
 
+
 # Set the 'development' global.
 . $srcdir/../../bfd/development.sh