On macOS, we set the install_name for built libraries to
@rpath/libfoo.dylib, and when linking to the library, we set the RPATH
to its path in the build directory. This allows all built binaries to
be run as-is from the build directory (uninstalled).
However, on install, we have to strip all the RPATHs because they
point to the build directory, and we change the install_name of all
built libraries to the absolute path to the library. This causes the
install name in binaries to be out of date.
We now change that install name to point to the absolute path to each
built library after installation.
Fixes https://github.com/mesonbuild/meson/issues/3038
Fixes https://github.com/mesonbuild/meson/issues/3077
With this, the default workflow on macOS matches what everyone seems
to do, including Autotools and CMake. The next step is providing a way
for build files to override the install_name that is used after
installation for use with, f.ex., private libraries when combined with
the install_rpath: kwarg on targets.
Otherwise we can end up searching for the same library tens of times,
because pkg-config does not de-duplicate -lfoo args before returning
them.
We use -Wl,--start-group/end-group, so we do not need to worry about
ordering issues in static libraries.
* mesonbuild/compilers/c.py: Make the `find_library` method more generic by allowing the user to supply the `code` for compiling and linking.
* mesonbuild/compilers/fortran.py: Use the methods inherited from `Compiler` base class where appropriate. Also reuse `CComiler` methods where applicable. This should be sufficient to get various compiler/linker arguments as well as to compile and link Fortran programs. This was tested with `gfortran` compiler, and while the other compilers ought to work for simple cases, their methods are primarily inherited from the base `FortranCompiler` class.
* test cases/fortran/10 find library/gzip.f90: Fortran module with some basic Fortran wrapper interfaces to `gzopen`, `gzwrite`, and `gzclose` C `zlib` functions.
* test cases/fortran/10 find library/main.f90: Fortran program using the `gzip` Fortran interface module to write some data to a gzip file.
* test cases/fortran/10 find library/meson.build: Meson build file for this test case. This demonstrates the ability to link the Fortran program against an external library.
This patch exploits the information residing in ltversion to set the
-compatibility_version and -current_version flags that are passed to the
linker on macOS.
According to Python documentation[1] dirname and basename
are defined as follows:
os.path.dirname() = os.path.split()[0]
os.path.basename() = os.path.split()[1]
For the purpose of better readability split() is replaced
by appropriate function if only one part of returned tuple
is used.
[1]: https://docs.python.org/3/library/os.path.html#os.path.split
Nirbheek Chauhan