Jon Turney authored Jul 11, 2014 and Hugo Beauzée-Luyssen committed Dec 20, 2017

- Link minidump_stackwalk, minidump_dump, microdump_stackwalk with
PTHREAD_LIBS as pthread_cancel is used

- Link minidump_stackwalk, microdump_stackwalk, binarystream_unittest with
ws2_32 as ntoh functions are used

- _s function variants should only be used if _MSC_VER, use _r variants with
MinGW (and define _POSIX_C_SOURCE to ensure they are prototyped)

 - Don't try to build upload tools, dump_syms_dwarf for MinGW

(Part of https://breakpad.appspot.com/548002 was commited as svn r1399 to
fix breakpad client compilation for MinGW

This is mainly the configure.ac and Makefile.am changes left over from
https://breakpad.appspot.com/548002/ with a bit of updating, to fix building
of the minidump processor library and tools for MinGW)

v2:
Use _POSIX_C_SOURCE not _POSIX to enable *_r() prototypes in headers

The headers seem to have changed so localtime_r() prototype is now guarded
by _POSIX_C_SOURCE

This seems right anyhow as _POSIX_C_SOURCE is what SUS defines, whereas I
think _POSIX is some left-over Interix thing?

v3:
Drop _snprintf fix, now dealt with centrally and correctly since 48673cdb