Re: rebuild when flags change

[Iwan Aucamp]

 On 09/15/2010 05:44 AM, Lynn Lin wrote:
>        Our build command
>        $(QUIET_CPP)$(CPP) $(CPPFLAGS) $(CXXFLAGS) $(INCLUDES) -c $<
>
>        when CPPFLAGS change,how can we enable make rebuild?


This might not be the best idea, and I have not yet implemented it in 
our build, but what I could come up with was to write all variables 
$(.VARIABLES) to a file (key and value, sorted by key) on each run and 
then on the next run do this again, take hash of old and new and if hash 
differs then touch a file which is as a dependency of all other files.

Possibly you could do the same with shell environment ( $(shell set) or 
$(shell env) ).