Fix libcaf_shmem build on Solaris.
This commit fixes a build failure for libcaf_shmem on Solaris by renaming a conflicting type definition.
The libcaf_shmem component of libgfortran failed to build on Solaris due to a conflicting definition of lock_t. This commit resolves the conflict by renaming the type to caf_shmem_lock_t. The fix ensures that libcaf_shmem can be built on Solaris systems and maintains compatibility.
In Details
This patch addresses a naming conflict in libcaf_shmem on Solaris-based systems. The lock_t type, defined as caf_shmem_mutex in caf/shmem/sync.h, clashed with an existing lock_t in the Solaris system headers (/usr/include/ia32/sys/machtypes.h). Renaming the type to caf_shmem_lock_t resolves the conflict without altering functionality. This issue primarily affects Solaris users of libcaf_shmem.
For Context
This commit fixes an error that prevented a part of the Fortran standard library, libcaf_shmem, from being compiled on Solaris operating systems. The error occurred because two different parts of the software were trying to define the same term, lock_t, in conflicting ways. To resolve this, the Fortran library's definition was renamed to avoid the conflict, allowing the library to be built and used correctly on Solaris. This ensures that programs using this library will now work as expected on Solaris.