Features: Fix the default C dialect for Clang and GNU.

Clang 3.4 uses C99 by default, and Clang 3.6 uses C11 by default:

 http://thread.gmane.org/gmane.comp.compilers.clang.devel/39379

GNU 4.9 uses C90 by default, and GNU 5.0 uses C11 by default:

 https://gcc.gnu.org/gcc-5/changes.html

Test that the default compiler settings result in the expected dialect
macros being defined for both C and CXX.  Remove the unused main.c
file from the CompileFeatures unit test.

1 files changed, 22 insertions, 0 deletions

diff --git a/Tests/CompileFeatures/default_dialect.c b/Tests/CompileFeatures/default_dialect.c
new file mode 100644
index 0000000..1b39dec
--- /dev/null
+++ b/Tests/CompileFeatures/default_dialect.c
@@ -0,0 +1,22 @@
+
+#if DEFAULT_C11
+#  if __STDC_VERSION__ != 201112L
+#    error Unexpected value for __STDC_VERSION__.
+#  endif
+#elif DEFAULT_C99
+#  if __STDC_VERSION__ != 199901L
+#    error Unexpected value for __STDC_VERSION__.
+#  endif
+#else
+#  if !DEFAULT_C90
+#    error Buildsystem error
+#  endif
+#  if defined(__STDC_VERSION__)
+#    error Unexpected __STDC_VERSION__ definition
+#  endif
+#endif
+
+int main()
+{
+  return 0;
+}