Fixes https://github.com/behdad/harfbuzz/issues/146
Or I think it should.
/* Note: C++ allows sizeof() of variable-lengh arrays. So, if _cond is not
* constant, it still compiles (ouch!), but at least we'll get a -Wvla warning. */
-#define ASSERT_STATIC_EXPR_ZERO(_cond) (0 * sizeof (char[(_cond) ? 1 : -1]))
+#define ASSERT_STATIC_EXPR_ZERO(_cond) (0 * (unsigned int) sizeof (char[(_cond) ? 1 : -1]))
#define _PASTE1(a,b) a##b
#define PASTE(a,b) _PASTE1(a,b)