configure: Do stricter GCC checking.

$GCC might be true for clang as well but clang does not support gcov coverage
testing.

diff --git a/configure.ac b/configure.ac
index d927b60a939ce2533a297170d9afb97ce74b0587..4977fb5986b7c4902a120fce4415609731128976 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -191,9 +191,21 @@ AC_ARG_ENABLE([gcov],
                [enable_gcov="$enableval"],
                [enable_gcov="no"])
 
+dnl $GCC is based on some heuristics which might apply to clang as well.
+dnl However, clang does not support gcov.
+cc_is_gcc="no"
+case "x$CC" in
+       gcc)
+               cc_is_gcc="yes"
+               ;;
+       gcc-*)
+               cc_is_gcc="yes"
+               ;;
+esac
+
 COVERAGE_CFLAGS=""
 COVERAGE_LDFLAGS=""
-if test "x$enable_gcov" = "xyes" && test "x$GCC" == "xyes"; then
+if test "x$enable_gcov" = "xyes" && test "x$GCC$cc_is_gcc" == "xyesyes"; then
        COVERAGE_CFLAGS="-O0"
        cov_flag_have_problem="no"