configure: remove C diagnostic options under C++.

* configure (cplusplus): New variable.
Check ccname and cc for signs of C++; if so, set the new
variable to 'y'.  If the variable is set, then filter
C-specific options out of diag_flags.

1 files changed, 34 insertions, 0 deletions

diff --git a/configure b/configure
index aaf8217b..cc6d44a8 100755
--- a/configure
+++ b/configure
@@ -118,6 +118,7 @@ cross=
 compiler_prefix=
 ccname='$(CC)'
 cc='$(cross)$(compiler_prefix)$(ccname)'
+cplusplus=
 intptr=
 exe=
 tool_prefix=
@@ -698,6 +699,39 @@ else
   build_in_srcdir=y
 fi
 
+printf "Are we using a C++ compiler ..."
+
+case $ccname in
+*'++' | *'$(CXX)' )
+   cplusplus=y
+   ;;
+esac
+
+case $cc in
+*'++' | '$(CXX)' )
+  cplusplus=y
+  ;;
+esac
+
+if [ $cplusplus ] ; then
+   printf "yes\n"
+   set -- $diag_flags
+   diag_flags=''
+   for flag in "$@" ; do
+     case $flag in
+       *=implicit-function-declaration | \
+       *=missing-prototypes | \
+       *=strict-prototypes )
+       continue
+       ;;
+     esac
+     diag_flags="$diag_flags $flag"
+   done
+   diag_flags=${diag_flags# }
+else
+   printf "no\n"
+fi
+
 gen_config_make()
 {
   cat > config.make <<!