Refresh MIPS GCC 4.7 toolchain with MXU support

Change-Id: I3207da62af59a66ae53e94b8b0f657817f747db8
Always include CLEAR_VARS in Android.mk

Otherwise build may terminate with error message reads

  ... Cannot set module stem for a library

Change-Id: I4448b7b56eb7c26dd079a429c1a864b7abe5256c
Merge "Always include CLEAR_VARS in Android.mk"
Merge "Refresh MIPS GCC 4.7 toolchain with MXU support"
Fix gdb python support for Android platform debugging

GDB with python support looks for specfic set of locations for PYTHONHOME.
Add one more clue to find $ANDROID_BUILD_TOP/prebuilts/python/linux-x86/2.7.5
Note that ANDROID_BUILD_TOP is set by doing usual setup in Android development,
ie.

  . build/envsetup.sh
  lunch ...

Change-Id: Id75d6852e68af41480def264cb18a51b1e19ea86
Merge "Fix gdb python support for Android platform debugging"