Detecting Makefile changes in incremental builds.

[Krzysztof Cieniuch]

Hi,
I've implemented build system that uses advanced auto-dependency 
generation as described by Paul Smith
All works fine except one thing : if user changes compilation flags 
(e.g. modifies  CFLAGS that are set in Makefile) or modifies list of 
libraries to link with (e.g. via LDFLAGS) make obvoiusly can't detect 
this. To fix that one may add Makefile itself as a prerequisite to all 
object files and library/executable targets but that seems an overkill 
any change in Makefile will cause full rebuild of all targets in that 
Makefile.

Is there more intelligent solution to this problem ?

I was thinking about creating checksum from options passed to compiler 
and store them in deps files similar to file dependency information but 
how could I  tell make to mark target out of date if some checksum 
doesn't match previously computed ?

Thanks
Chris