Refresh MIPS GCC 4.7 toolchain with MXU support

Change-Id: I9d22192c56f48f0cf17d7c8f38db2c365aa0ca8f
Merge "Refresh MIPS GCC 4.7 toolchain with MXU support"
Always include CLEAR_VARS in Android.mk

Otherwise build may terminate with error message reads

  ... Cannot set module stem for a library

Change-Id: I67b4cfde42eab74193f5ba12537256fb5e0fae68
Merge "Always include CLEAR_VARS in Android.mk"
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: I0b4db61aa392bd2c09b29ac224e74465fd19a1d6
Merge "Fix gdb python support for Android platform debugging"
Fix GCC 4.7 MIPS ICE at dwarf2out.c

See https://android-review.googlesource.com/#/c/68810

Change-Id: I4110d52a0330138f552c00052a50f0fb2f90f0e1
Merge "Fix GCC 4.7 MIPS ICE at dwarf2out.c"