set CMAKE_COMPILER_ID to GNU in iOS toolchain

The current ios toolchain is GNU based but the iOSToolchain.cmake
set the CMAKE_COMPILER_ID to gcc which isn't known by cmake.
Merge pull request #1038 from bmiklautz/ioscompilerdetection

set CMAKE_COMPILER_ID to GNU in iOS toolchain
codec/nsc: fixed typo
Allow fullscreen toggle per default
iOS: correctly refresh screen after resize
Merge pull request #1039 from bmiklautz/togglefs

Allow fullscreen toggle per default
Merge pull request #1041 from mfleisz/iosresize

iOS: correctly refresh screen after resize