CoCoA » CoCoALib

Here is a copy of #1700#note-5 (which I closed because it duplicates this issue).

I wonder if there is a simple away to warn users of potential problems?

A similar problem could arise with any of the external libs, and the
solution is no doubt to rebuild dependencies -- and this should normally
be done by re-running configure (which may include some other "sanity
checks" for external libs).

Here is an idea:
for each ext lib configure computes a check-sum for some header file
in that ext lib, and saves the result in autoconf.mk. Then make
can verify that the check-sums are correct -- if not, a warning with
a delay, can be produced before proceeding with compilation.
[the delay gives the user a chance to hit Ctrl-C]