configure: Check build with some header not just preprocessing for testing --std=c11

Fixes build failure on FreeBSD with gcc 4.7

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

configure

@@ -1201,13 +1201,15 @@ check_cpp_condition(){
 EOF
 }
 
-test_cflags_cpp(){
-    log test_cflags_cpp "$@"
+test_cflags_cc(){
+    log test_cflags_cc "$@"
     flags=$1
-    condition=$2
-    shift 2
+    header=$2
+    condition=$3
+    shift 3
     set -- $($cflags_filter "$flags")
-    check_cpp "$@" <<EOF
+    check_cc "$@" <<EOF
+#include <$header>
 #if !($condition)
 #error "unsatisfied condition: $condition"
 #endif
@@ -4625,7 +4627,7 @@ add_cxxflags -std=c++98
 
 # some compilers silently accept -std=c11, so we also need to check that the
 # version macro is defined properly
-if test_cflags_cpp -std=c11 "__STDC_VERSION__ >= 201112L"; then
+if test_cflags_cc -std=c11 ctype.h "__STDC_VERSION__ >= 201112L"; then
     add_cflags -std=c11
 else
     check_cflags -std=c99