D lang compilers have an option -release (or similar) which turns off
asserts, contracts, and other runtime type checking. This patch wires
that up to the b_ndebug flag.
Fixes#7082
* 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.