Fix building ARMv7 on the 64bit Android NDK.

Google has gotten their act together and fixes a few of the signal handling headers.
Change over to a header that works on both r10 32bit and r10 64bit.
32bit has the old "broken" headers as in some didn't even exist.
64bit has the "fixed" headers that one would expect on any regular unix system.
Merge pull request #1034 from Sonicadvance1/fix-android-arm-ndk64bit

Fix building ARMv7 on the 64bit Android NDK.