Hi Peter. On 01/20/2012 12:56 PM, Peter Rosin wrote: > Stefano Lattarini skrev 2012-01-19 14:55: > > [MEGA-SNIP] > >> +# Prefer generic compilers to GNU ones when possible. This will ensure >> +# more testsuite coverage "in the wild". >> +# FIXME: maybe we should a more comprehensive list too look for more >> +# FIXME: "exotic" compilers? And what about looking also for the MSVC >> +# FIXME: compiler on Cygwin/MinGW systems? >> +_AM_COMPILER_CAN_FAIL([AC_PROG_CC([cc gcc])], [CC=false]) > > Looking for MSVC on Cygwin is a definite no, IMHO. MSVC can't produce > Cygwin programs (I have never heard of it anyway, maybe with -nodefaultlib > and adding a bunch of low level cygwin stuff instead, but I highly doubt > it will fly), so it can only be viewed as a cross compiler in that > setting. IOW, the same as looking for it on Linux with Wine/binfmt-misc... > BTW, that's a good starting point for how Cygwin should be viewed when it > comes to build systems; as Linux with Wine and binfmt-misc set up to > handle PE stuff. > > MinGW is another matter... > Thanks for the detailed information. I'll adjust the FIXME comment accordingly.
>> + >> +# The list of C++ compilers here has been copied, pasted and edited >> +# from `lib/autoconf/c.m4:AC_PROG_CXX' in the Autoconf distribution. >> +# Keep it in sync, or better again, find out a way to avoid this code >> +# duplication. >> +_AM_COMPILER_CAN_FAIL([AC_PROG_CXX(dnl >> + [aCC CC cl.exe FCC KCC RCC xlC_r xlC c++ cxx cc++ gpp g++])], >> + [CXX=false]) > > I suppose it can be a problem that cl.exe is before g++ on Cygwin or Linux > with Wine/binfmt-misc and if MSVC is installed (and visible), when cl.exe > is best viewed as a cross compiler in those cases. > Are you afraid that configure will, in such a setup, automatically (and erroneously) determine that we are *not* cross compiling, while in fact we are? If yes, I agree that would be problematic. Maybe we could (in a follow-up patch) avoid looking for cl.exe if we determine the current build system is Cygwin? Ugly, but easy to do (and also correct, I hope). > But I usually don't > source my script that adds MSVC to PATH and sets up various other bits > needed in the environment when in Cygwin, so cl.exe isn't normally on my > PATH so it wouldn't be a problem *for me*. But I think there is an option > to add MSVC to the "global" environment though, and if that has been done, > it might not be so easy to avoid finding MSVC from Cygwin. > So the hack I have proposed above might be necessary after all. Damn. I will await confirmation from you that I have inderstood the situation correctly, before proceeding to write a patch. Thanks again for your responsiveness and support, Stefano
