#287 More reliable Android platform detection

[Maxym]

Hello again!

While working on iOS build, I found a bug in the root CMakeLists.txt.
Whenever I provide cmake toolchain file, the script thinks that I'm building for Android.
So, I changed it to check the name of the toolchain file provided.

Please, check the patch, and if it's ok, apply it ;)

Based on v.1.1.2

Thanks in advance!
Maxym

[Václav Haisman]

Applied.