automake 1.12 changed the default for tests, requiring projects
that need serial test execution to add an option for setting this.
This option isn't available on automake 1.11, so those projects
became incompatible with automake 1.11 once they got ready for 1.12.
This obviously isn't an issue in most cases where the prebuilt
configure is good enough.

Since we don't run the tests in contribs, just remove this option
for now, to allow building with both automake 1.11 and 1.12.
Signed-off-by: Martin Storsjö <martin@martin.st>

_set_invalid_parameter_handler is now usable in recent versions of mingw-w64

This reverts commit acf5397b.

Conflicts:
	contrib/src/bghudappkit/rules.mak

This reverts commit c16bc980.
This is no longer applicable with current libav HEAD.

http://msdn.microsoft.com/en-us/library/b0084kay(v=vs.80).aspx only
mentions the _ prefixed variable.

gcc will always define the _ prefixed variable, like Visual Studio.
The prefixless one is defined in some language standards, e.g. gnu99
but not c99.

Those Windows functions bring no benefit and are forbidden in Windows Store apps

Hopefully, we are closer to an upstream release

Better fall back to software decoding than crash.

All the versions we support can use UTF8