Add an autoconf test to check for optional compiler flags like
-Wno-missing-field-initializers or -Wno-variadic-macros.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85147 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/autoconf/configure.ac b/autoconf/configure.ac
index b9ad6bb..794326d 100644
--- a/autoconf/configure.ac
+++ b/autoconf/configure.ac
@@ -943,6 +943,12 @@
dnl Tool compatibility is okay if we make it here.
AC_MSG_RESULT([ok])
+dnl Check optional compiler flags.
+AC_MSG_CHECKING([optional compiler flags])
+CXX_FLAG_CHECK(NO_VARIADIC_MACROS, [-Wno-variadic-macros])
+CXX_FLAG_CHECK(NO_MISSING_FIELD_INITIALIZERS, [-Wno-missing-field-initializers])
+AC_MSG_RESULT([$NO_VARIADIC_MACROS $NO_MISSING_FIELD_INITIALIZERS])
+
dnl===-----------------------------------------------------------------------===
dnl===
dnl=== SECTION 5: Check for libraries
diff --git a/autoconf/m4/cxx_flag_check.m4 b/autoconf/m4/cxx_flag_check.m4
new file mode 100644
index 0000000..ab09f2a
--- /dev/null
+++ b/autoconf/m4/cxx_flag_check.m4
@@ -0,0 +1,2 @@
+AC_DEFUN([CXX_FLAG_CHECK],
+ [AC_SUBST($1, `$CXX $2 -fsyntax-only -xc /dev/null 2>/dev/null && echo $2`)])