+
+CLANG_VERSION=none
+
+if test "x$ifelse([$2],,CLANG_COMPILER,[$2])" = "xyes" ; then
+ case "$CC" in
+ (c[[1-9]][[0-9]]|*/c[[1-9]][[0-9]])
+ AC_MSG_WARN(replacing broken compiler alias $CC)
+ CFLAGS="$CFLAGS -std=`echo "$CC" | sed -e 's%.*/%%'`"
+ CC=clang
+ ;;
+ esac
+
+ AC_MSG_CHECKING(version of $CC)
+ CLANG_VERSION="`$CC --version 2>/dev/null | sed -e '2,$d' -e 's/^.*(CLANG[[^)]]*) //' -e 's/^.*(Debian[[^)]]*) //' -e 's/^[[^0-9.]]*//' -e 's/[[^0-9.]].*//'`"
+ test -z "$CLANG_VERSION" && CLANG_VERSION=unknown
+ AC_MSG_RESULT($CLANG_VERSION)
+
+ for cf_clang_opt in \
+ -Qunused-arguments \
+ -Wno-error=implicit-function-declaration
+ do
+ AC_MSG_CHECKING(if option $cf_clang_opt works)
+ cf_save_CFLAGS="$CFLAGS"
+ CFLAGS="$CFLAGS $cf_clang_opt"
+ AC_TRY_LINK([
+ #include <stdio.h>],[
+ printf("hello!\\n");],[
+ cf_clang_optok=yes],[
+ cf_clang_optok=no])
+ AC_MSG_RESULT($cf_clang_optok)
+ CFLAGS="$cf_save_CFLAGS"
+ if test "$cf_clang_optok" = yes; then
+ CF_VERBOSE(adding option $cf_clang_opt)
+ CF_APPEND_TEXT(CFLAGS,$cf_clang_opt)
+ fi
+ done
+fi