Target-specific CPPFLAGS for autodependencies

[David Greene]

I use target-specific variable definitions for things like CFLAGS
and CPPFLAGS.

Unfortunately, GNU make's ability to automatically make makefiles
can't take advantage of this:

prog: CPPFLAGS = -I/my/include/dir
prog: file1.o file2.o

%.d: %.c
        $(CC) -MM $(CPPFLAGS) $< > $@

include file1.d file2.d

Since the rule that makes file.d and file2.d is not invoked
as a dependency of prog, CPPFLAGS is not set to the correct
value.

What's the right way to do this?  I have a number of dependency
includes which need to use different CPPFLAGS to search different
header directories.  I'd rather not have to define prog_CPPFLAGS,
prog2_CPPFLAGS and then do some command magic to use the right
variable in the $(CC) -MM invocation depending on the value of address@hidden

Thanks again.

                 -Dave