Fix build system for C++ unit tests: correctly compile TestSupport.h.gch
Fix build system for C++ unit tests: correctly compile TestSupport.h.gch

clemensg/passenger,phusion/passenger,phusion/passenger,clemensg/passenger,phusion/passenger,phusion/passenger,clemensg/passenger,clemensg/passenger,phusion/passenger,phusion/passenger,clemensg/passenger,clemensg/passenger,clemensg/passenger,phusion/passenger,phusion/passenger,clemensg/passenger