fixup??? git-compat-util: add a test balloon for C99 support

This seems to be required to define `FLEX_ARRAY` in a manner that MSVC
in C11 mode accepts.

Signed-off-by: Johannes Schindelin <[email protected]>

Author: dscho

git-compat-util.h

@@ -46,7 +46,7 @@
 /*
  * See if our compiler is known to support flexible array members.
  */
-#if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) && (!defined(__SUNPRO_C) || (__SUNPRO_C > 0x580))
+#if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) && !defined(_MSC_VER) && (!defined(__SUNPRO_C) || (__SUNPRO_C > 0x580))
 # define FLEX_ARRAY /* empty */
 #elif defined(__GNUC__)
 # if (__GNUC__ >= 3)