fixdep: faster CONFIG_search
This is a port of dee81e988674 from Linux ("fixdep: faster CONFIG_ search") and posted by itself for ease of review. To quote the kernel changelog: "Do you think kernel build is 100% dominated by gcc? You are wrong! One small utility called "fixdep" consistently manages to sneak into profile's first page (unless you have small monitor of course). The choke point is this clever code: for (; m < end; m++) { if (*m == INT_CONF) { p = (char *) m ; goto conf; } if (*m == INT_ONFI) { p = (char *) m-1; goto conf; } if (*m == INT_NFIG) { p = (char *) m-2; goto conf; } if (*m == INT_FIG_) { p = (char *) m-3; goto conf; } 4 branches per 4 characters is not fast. Use strstr(3), so that SSE2 etc can be used. With this patch, fixdep is so deep at the bottom, it is hard to find it." Cc: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by:Tom Rini <trini@konsulko.com> --- As part of working to re-sync our kbuild logic I see that fixdep.c wasn't updated as part of the general resync with v4.17. As this specific change required some thinking to adapt our logic that was added in 8be60f06 I am posting this change stand-alone for review.