http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49576
--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> 2011-06-29 17:34:11 UTC --- If your program has: #include "everything.h" #include <something.h> and you have a PCH for everything.h.gch then something.h should be added to everything.h Isn't that easy enough? I don't understand why only headers under /usr/include would be potentially added, that's not the only use case for PCH