Hi, Fredrik Kuivinen wrote: > Previously you had to manually define COMPUTE_HEADER_DEPENDENCIES to > enable this feature. It seemed a bit sad that such a useful feature > had to be enabled manually. Yes! Thanks for this. I have a few thoughts about the implementation: > --- a/Makefile > +++ b/Makefile [...] > @@ -1236,6 +1232,15 @@ endif > ifdef CHECK_HEADER_DEPENDENCIES > COMPUTE_HEADER_DEPENDENCIES = > USE_COMPUTED_HEADER_DEPENDENCIES = > +else > +dep_check = $(shell sh -c \ > + ': > ++empty.c; \ > + $(CC) -c -MF /dev/null -MMD -MP ++empty.c -o /dev/null 2>&1; \ > + echo $$?; \ > + $(RM) ++empty.c') > +ifeq ($(dep_check),0) > +COMPUTE_HEADER_DEPENDENCIES=YesPlease > +endif This causes "make foo" to run gcc and create a temporary file unconditionally, regardless of what foo is. In an ideal world: - the autodetection would only happen when building targets that care about it - the detection would happen once (creating some file to store the result) and not be repeated with each invocation of "make" - (maybe) there would be a way to override the detection with either a "yes" or "no" result, for those who really care to save a little time. I was about to say that the GIT_VERSION variable has some of these properties, but now that I check, from the point of view of the Makefile it doesn't. ./GIT-VERSION-GEN is just very fast. :) I wonder if we can make do with a faster check, like $(CC) -c -MF /dev/null -MMD -MP git.c --help >/dev/null 2>&1 What do you think? -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html