graphics/rawtherapee: Update 5.12 => 5.13

Extend patch for rtengine/LibRaw.cmake to properly forward our local
CXXFLAGS (available through ${CMAKE_CXX_FLAGS} inside cmake) to the
libraw build, else it will build against GCC's default Standard C++
Library, which might be libstdc++, which then breaks when doing the
final link against the common libc++ based system (GNU libstdc++ and
LLVM's libc++ have incompatible ABIs).

Switch to using the system libfmt, which is version 12 and good.

Changelog: https://rawtherapee.com/downloads/5.13/
PR: 297513
Reported by: mandree (maintainer)
Approved by: osa, vvd (Mentors, implicit)
Pull Request: https://github.com/freebsd/freebsd-ports/pull/581