deleting config.cache upon CFLAGS variable change

[Mathieu Lacage]

hi,

Recently, I discovered the "./configure CFLAGS=-O0" syntax:
previously, I used to do "CFLAGS=-O0 ./configure" (I wonder if they
are really equivalent but, this is not really my main question today).

So, anyway, I use "./configure CFLAGS=-O0" and I regularly switch to
"./configure CFLAGS=-O2". I would like to know if deleting
config.cache is sufficient to ensure that the build is correct or if I
should "make distclean" instead. A couple of tests done by building
the gdb tarball appear to show that "make distclean" is the only way
to ensure that the new build obeys the new flags.

If so, my question is: is there a programatic way to check whether or
not the flags I am asking configure to use are different from the old
ones so that I can "make distclean" only when needed ?

Mathieu
-- 
Mathieu Lacage <address@hidden>