Attempt #2 to fix mingw crossbuild. This time with more ugly hacks!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147196 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/configure b/configure
index 62b2d1c..7c86dbf 100755
--- a/configure
+++ b/configure
@@ -20986,14 +20986,14 @@
 ac_compiler_gnu=$ac_cv_cxx_compiler_gnu
 
   oldcxxflags="$CXXFLAGS"
-  CXXFLAGS="$CXXFLAGS -fvisibility-inlines-hidden"
+  CXXFLAGS="$CXXFLAGS -fvisibility-inlines-hidden -Werror"
   cat >conftest.$ac_ext <<_ACEOF
 /* confdefs.h.  */
 _ACEOF
 cat confdefs.h >>conftest.$ac_ext
 cat >>conftest.$ac_ext <<_ACEOF
 /* end confdefs.h.  */
-template <typename T> struct X { inline void f() {} };
+template <typename T> struct X { void __attribute__((noinline)) f() {} };
 int
 main ()
 {