http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19541
--- Comment #23 from Rodolfo Schulz de Lima <rodolfo at rodsoft dot org> --- How difficult is it to add a parameter to add paths to precompiled header search list *only*? We have a big code base with #include "pch.h" in some source files. If source file directory is always searched first for headers, this breaks out-of-source builds, unless the precompiled header is generated in the source tree. For read-only source trees, this "solution" is unacceptable. The ideal solution would be a parameter like -ipch <path> that adds <path> to be searched for precompiled headers *before* the current source directory. I could spend some time creating a patch, but seeing that others have come with patches that weren't applied, this kind of demotivate me.