When cross compiling a target gcc, target flags may be used on the host

Configure identifies a number of warning flags (WARN_CFLAGS and 
WARN_CXXFLAGS) from the $CC value.  The cross compiler may be different
from the host compiler and may not support the same set of flags.  This
leads to problems such as:

cc1plus: error: unrecognized command line option "-Wno-narrowing"
cc1plus: error: unrecognized command line option "-Wno-overlength-strings"

Work around this problem by removing the warning flags from the
BUILD_*FLAGS values.

Upstream-Status: Pending

Signed-off-by: Mark Hatle <mark.hatle@windriver.com>

diff -ur gcc-4.8.0.orig/gcc/configure.ac gcc-4.8.0/gcc/configure.ac
--- gcc-4.8.0.orig/gcc/configure.ac	2013-05-29 14:44:24.960853593 -0500
+++ gcc-4.8.0/gcc/configure.ac	2013-05-31 01:34:09.518775962 -0500
@@ -1892,8 +1892,8 @@
 # These are the normal (build=host) settings:
 CC_FOR_BUILD='$(CC)'		AC_SUBST(CC_FOR_BUILD)
 CXX_FOR_BUILD='$(CXX)'		AC_SUBST(CXX_FOR_BUILD)
-BUILD_CFLAGS='$(ALL_CFLAGS)'	AC_SUBST(BUILD_CFLAGS)
-BUILD_CXXFLAGS='$(ALL_CXXFLAGS)' AC_SUBST(BUILD_CXXFLAGS)
+BUILD_CFLAGS='$(ALL_BUILD_CFLAGS)'	AC_SUBST(BUILD_CFLAGS)
+BUILD_CXXFLAGS='$(ALL_BUILD_CXXFLAGS)' AC_SUBST(BUILD_CXXFLAGS)
 BUILD_LDFLAGS='$(LDFLAGS)'	AC_SUBST(BUILD_LDFLAGS)
 STMP_FIXINC=stmp-fixinc		AC_SUBST(STMP_FIXINC)
 
diff -ur gcc-4.8.0.orig/gcc/Makefile.in gcc-4.8.0/gcc/Makefile.in
--- gcc-4.8.0.orig/gcc/Makefile.in	2013-05-29 14:44:24.369853593 -0500
+++ gcc-4.8.0/gcc/Makefile.in	2013-05-31 01:34:30.360776427 -0500
@@ -989,10 +989,16 @@
 ALL_CFLAGS = $(T_CFLAGS) $(CFLAGS-$@) \
   $(CFLAGS) $(INTERNAL_CFLAGS) $(COVERAGE_FLAGS) $(WARN_CFLAGS) @DEFS@
 
+ALL_BUILD_CFLAGS = $(T_CFLAGS) $(CFLAGS-$@) \
+  $(CFLAGS) $(INTERNAL_CFLAGS) @DEFS@
+
 # The C++ version.
 ALL_CXXFLAGS = $(T_CFLAGS) $(CFLAGS-$@) $(CXXFLAGS) $(INTERNAL_CFLAGS) \
   $(COVERAGE_FLAGS) $(NOEXCEPTION_FLAGS) $(WARN_CXXFLAGS) @DEFS@
 
+ALL_BUILD_CXXFLAGS = $(T_CFLAGS) $(CFLAGS-$@) $(CXXFLAGS) $(INTERNAL_CFLAGS) \
+  $(NOEXCEPTION_FLAGS) @DEFS@
+
 # Likewise.  Put INCLUDES at the beginning: this way, if some autoconf macro
 # puts -I options in CPPFLAGS, our include files in the srcdir will always
 # win against random include files in /usr/include.