Revert "Revert "Introduce CC/CXX/JAVAC_WRAPPER to wrap the calls to clang.""

This reverts commit a4f84fdfed9a805d69b37de997512cd0616b3ff8.
Added "export CCACHE_CPP2 := true" to work around ccache bug with clang.
See:
http://petereisentraut.blogspot.com/2011/09/ccache-and-clang-part-2.html

Change-Id: I2b1fa8fd59c3a113c4028a92a1d16018133c9792
2 files changed