https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105355
--- Comment #3 from Alexey Izbyshev <izbyshev at ispras dot ru> --- (In reply to Martin Liška from comment #2) Yes, "gcc test.h -o test.pch" uses the separate spelling of "--output-pch=" in cc1 command line (but, curiously, "gcc test.h" uses the joined spelling).