ASan uses GetProcAddress to get the address of malloc so it can patch
it. Newer versions of Windows make GetProcAddress initialize the DLL
before returning a function pointer into it. That's perfectly
reasonable, but ASan needs to finish patching malloc before CRT
initialization. So now we roll our own GetProcAddress.
Fixes PR24237
Based on a patch by David Major
Originally written by David Major as part of:
https://hg.mozilla.org/mozilla-central/file/tip/toolkit/xre/WindowsCrtPatch.h
llvm-svn: 245377
Reid Kleckner