diff --git a/gcc/configure b/gcc/configure
index fbdcd89..a2791a3 100755
--- a/gcc/configure
+++ b/gcc/configure
@@ -11704,6 +11704,7 @@ STMP_FIXINC=stmp-fixinc
 if test x$build != x$host || test "x$coverage_flags" != x
 then
     BUILD_CFLAGS='$(INTERNAL_CFLAGS) $(T_CFLAGS) $(CFLAGS_FOR_BUILD)'
+    BUILD_CXXFLAGS='$(INTERNAL_CFLAGS) $(T_CFLAGS) $(CXXFLAGS_FOR_BUILD)'
     BUILD_LDFLAGS='$(LDFLAGS_FOR_BUILD)'
 fi
 
diff --git a/gcc/configure.ac b/gcc/configure.ac
index 773cb5d..5d7d18b 100644
--- a/gcc/configure.ac
+++ b/gcc/configure.ac
@@ -1887,6 +1887,7 @@ STMP_FIXINC=stmp-fixinc		AC_SUBST(STMP_FIXINC)
 if test x$build != x$host || test "x$coverage_flags" != x
 then
     BUILD_CFLAGS='$(INTERNAL_CFLAGS) $(T_CFLAGS) $(CFLAGS_FOR_BUILD)'
+    BUILD_CXXFLAGS='$(INTERNAL_CFLAGS) $(T_CFLAGS) $(CXXFLAGS_FOR_BUILD)'
     BUILD_LDFLAGS='$(LDFLAGS_FOR_BUILD)'
 fi