This PR mainly exists as a reminder for myself, I have been bitten by this a couple of times while testing an unrelated patch and getting stumped by apparent major breakage. Inside the build tree, for each $module and $MULTIDIR, the files $target/$module/Makefile and probably also $target/$MULTIDIR/$module/Makefile have broken rules for the 'Makefile' target: when run, these rules just run './config.status Makefile', whereas the right thing to do would be to also run the './config.status default-1' config commands. FWIW, this is not important for a normal bootstrap, only for an incremental rebuild in which the respective Makefile.in file has been updated. IOW, in practice it can only happen with --enable-maintainer-mode or after a './contrib/gcc_update' which happened to update the Makefile.in files but not the respective configure files. To reproduce: in an up to date build tree with --enable-multilib, do touch $srcdir/libgomp/Makefile.in make and observe $target/libgomp/Makefile differences. Fix by rm -f $target/*/Makefile make I intend to eventually fix this, but it is low priority.
(In reply to Ralf Wildenhues from comment #0) > Inside the build tree, for each $module and $MULTIDIR, the files > $target/$module/Makefile and probably also > $target/$MULTIDIR/$module/Makefile have broken rules for the 'Makefile' > target: when run, these rules just run './config.status Makefile', > whereas the right thing to do would be to also run the > './config.status default-1' config commands. For modules that use automake, the rules that automake generates for the 'Makefile' target look like this: .PRECIOUS: Makefile Makefile: $(srcdir)/Makefile.in $(top_builddir)/config.status @case '$?' in \ *config.status*) \ echo ' $(SHELL) ./config.status'; \ $(SHELL) ./config.status;; \ *) \ echo ' cd $(top_builddir) && $(SHELL) ./config.status $@ $(am__depfiles_maybe)'; \ cd $(top_builddir) && $(SHELL) ./config.status $@ $(am__depfiles_maybe);; \ esac; Checking 'am__depfiles_maybe', it seems that automake sets it empty by default, so maybe 'default-1' needs to be added to 'am__depfiles_maybe' in the Makefile.am of any module that uses automake? (or whatever 'default-1' is called, that is; in my tree, I renamed the corresponding AC_CONFIG_COMMANDS argument in config/multi.m4 to say 'multilib-default-1' instead, as I find that more descriptive, but that would be a separate topic...)