The obtained binaries before and after this commit are identical (sha1sum)
when compiled in Debian/Ubuntu/Fedora/ArchLinux.
.
The linker will always pick the 32bit libraries the only thing this does is
make sure we have all the 32bit dependencies installed. Basically we avoid
detecting the 64bit libraries and telling the users the 32bit libraries were
found. We always link with 32bit libraries therefore this avoids having to
wait 5-10min to just be told -lXXX is missing.
.
The only thing really needed are
set(CMAKE_LIBRARY_ARCHITECTURE "../lib32")
set(CMAKE_LIBRARY_ARCHITECTURE ".")
.
which basically ensures we don't pick 64bit headers since
CMAKE_LIBRARY_ARCHITECTURE always gets tested first and for some reason
FindGTK2 test searches lib64 first then lib32/lib. These values are hardcoded.
Right now these arch specific headers are not used but can't say this will
always be true.
.
FIND_LIBRARY_USE_LIB64_PATHS is not needed for native builds and it's covered
by CMAKE_SYSTEM_IGNORE_PATH.
.
NOTE:
We filter out lib32 because multilib is not compatible with multiarch.
- Update the build.sh and fix some typos.
+ Don't add the OSX ones because I have not tested them and it won't
even build anyway due to the libaio dependency. Needs to use POSIX AIO
or something else.
- They are rather simple and all the magic happens in two lines.
+ First line tells cmake to get ready to compile FOR linux or darwin.
It also sets CMAKE_CROSSCOMPILING to true which is the only way to
let cmake known that we are using stuff not from the host.
+ CMAKE_C_COMPILER/CMAKE_CXX_COMPILER are basically used to detect
the architecture of the target. Since I used generic cc/c++ the
hardcoded -m32 is needed to ensure we get TARGET=i386. Also
since I hardcode -m32 and use c++/cc it's to be noted that
we can only do i386->i386 (trivial), amd64 -> i386, and x32->i386.
.
Using something like i586-linux-gnu-{gcc,g++} would also work and
enable arm -> i386, etc but it's infeasible and impractical to do all
the combinations. File is simple enough that a distro or user can
create their own and cross compiling is rather tedious compared
to using a chroot to compile it.
- I tested it in Debian with "dpkg-buildpackage -ai386" but installing the
build dependencies was rather tedious.
Gregory Hainaut