[freetype2] Temporarily disable function-type-mismatch checks

There's a lot of this type of UB in freetype2. Rather than fixing them
all to unblock the clang roll, just disable this check for now and come
back to fix them. Disabling this check is a no-op since prior to a
recent clang change, -fsanitize=function only worked on C++ code, but
freetype2 is all C, so these were already existing bugs.

Bug: 128274
Change-Id: Iec24ee73c2b2f42c858dd11000064a54794361b8
Reviewed-on: https://fuchsia-review.googlesource.com/c/third_party/freetype2/+/864797
Reviewed-by: Petr Hosek <phosek@google.com>
1 file changed