Makefile: add option to disable automatic dependency generation
Now that the COMPUTE_HEADER_DEPENDENCIES feature is turned on
automatically for compilers that support it (see v1.7.8-rc0~142^2~1,
2011-08-18), there is no easy way to force it off. For example,
setting COMPUTE_HEADER_DEPENDENCIES to the empty string in config.mak
just tells the makefile to treat it as undefined and run a test
command to see if the -MMD option is supported.
So allow setting COMPUTE_HEADER_DEPENDENCIES=no to explicitly force
the feature off. The new semantics:
- "yes" means to explicitly enable the feature
- "no" means to disable it
- "auto" means to autodetect
The default is still "auto". Any value other than these three will
cause the build to error out with a descriptive message so typos and
stale settings in config.mak don't result in mysterious behavior.
Makefile:1278: *** please set COMPUTE_HEADER_DEPENDENCIES to
yes, no, or auto (not "1"). Stop.
So now when someone using a compiler without -MMD support reports
trouble building git, you can reproduce it by running "make
Suggested-by: Nguyễn Thái Ngọc Duy <firstname.lastname@example.org>
Improved-by: Junio C Hamano <email@example.com>
Signed-off-by: Jonathan Nieder <firstname.lastname@example.org>
Tested-by: Nguyễn Thái Ngọc Duy <email@example.com>
Signed-off-by: Junio C Hamano <firstname.lastname@example.org>