MingW doesn't handle __attribute__((weak)) for Windows PE

Windows PE format doesn't have the same support for weak symbols
as ELF does.

The symbol android_log_id_to_name was strangely omitted from the
resulting Windows executable and the callsite where it was supposed
to be called was relaced with a different symbol, which caused a crash
in AAPT on Windows.

This change works due to a careful set of #ifdefs that ensure only one
definition of android_log_id_to_name is defined, but there are other
uses of __attribute__((weak)) which should be inspected.

Change-Id: I3b58076e31d9b28c5143773a170e9ffda9fa3815