The fact that the generated pch.h.gch is placed in the src tree rather than the build tree means that using different compilers to make separate builds is problematic. I get this warning:
cc1plus: warning: ./../../../../../src/frontends/qt2/ui/pch.h.gch: created on host `i686-pc-linux-gnu', but used on host `i386-redhat-linux-gnu' because I have a build-mingw-xcompile tree as well as my normal linux build. -- Angus
