Use the 4.8 gcc toolchain in conjunction with Clang for Android

That's what the $NDK/toolchains/arm-linux-androideabi-clang3.4/setup.mk does,
too.

Change-Id: I90555bc5f026761ebcf7a2dce650382b6c0d94da
Probably not a good idea to use gold with LTO

Change-Id: I72559ebabecad288f4c56bb9ff1eddbb498a2d35
No use to build tools or extras when cross-compiling

Also, for some reason building the endian check thing fails when trying to use
Clang for Android, so just hardcode it.

Change-Id: I04fb7ba4f88a1dc6a4e743b39e7c0cd19d7e3598
Pass -flto as part of CC and CXX when building external libs for Android

Using -flto and Clang still doesn't work, though, build stops already in
fontconfig. The linker claims the expat library doesn't have an archive symbol
table. Go figure, oh well, won't bother trying any more for now.

Change-Id: Icbd65269e958665704104322e66a5b3a78fac75e