Fix precompiled headers support detection for gcc-4.6 toolchain from Android NDK r8b
Fix precompiled headers support detection for gcc-4.6 toolchain from Android NDK r8b

The version reported by toolchain is 4.6.x-google so regex needs an adjustment.

opencv/opencv,opencv/opencv,apavlenko/opencv,opencv/opencv,apavlenko/opencv,apavlenko/opencv,opencv/opencv,apavlenko/opencv,opencv/opencv,opencv/opencv,apavlenko/opencv,opencv/opencv,opencv/opencv,apavlenko/opencv,opencv/opencv,opencv/opencv