[clang] [flang] [flang] Implement -mcmodel flag (PR #95411)

[LLVM Continuous Integration via cfe-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `libc-x86_64-debian-gcc-fullbuild-dbg` running on `libc-x86_64-debian-fullbuild` while building `clang,flang` at step 4 "annotate".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/131/builds/1365

Here is the relevant piece of the build log for the reference:
```
Step 4 (annotate) failure: 'python ../llvm-zorg/zorg/buildbot/builders/annotated/libc-linux.py ...' (failure)
...
-- lldb project is disabled
-- mlir project is disabled
-- openmp project is disabled
-- polly project is disabled
-- pstl project is disabled
-- flang project is disabled
-- Could NOT find LibEdit (missing: LibEdit_INCLUDE_DIRS LibEdit_LIBRARIES) 
Change Dir: /home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian-fullbuild/libc-x86_64-debian-gcc-fullbuild-dbg/build/CMakeFiles/CMakeTmp

Run Build Command(s):/usr/bin/ninja cmTC_abf7f && [1/2] Building CXX object CMakeFiles/cmTC_abf7f.dir/getErrc.cpp.o
FAILED: CMakeFiles/cmTC_abf7f.dir/getErrc.cpp.o 
/usr/bin/g++   -g -std=c++17 -o CMakeFiles/cmTC_abf7f.dir/getErrc.cpp.o -c /home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian-fullbuild/libc-x86_64-debian-gcc-fullbuild-dbg/build/CMakeFiles/CMakeTmp/getErrc.cpp
/home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian-fullbuild/libc-x86_64-debian-gcc-fullbuild-dbg/build/CMakeFiles/CMakeTmp/getErrc.cpp:15:9: fatal error: error writing to /tmp/ccJpSZaj.s: No space left on device
   15 |         }
      |         ^
compilation terminated.
ninja: build stopped: subcommand failed.


-- Failed to get errc messages
-- LLVM host triple: x86_64-unknown-linux-gnu
-- Native target architecture is X86
-- Threads enabled.
-- Doxygen disabled.
-- Ninja version: 1.11.1
-- Could NOT find OCaml (missing: OCAMLFIND OCAML_VERSION OCAML_STDLIB_PATH) 
-- Could NOT find OCaml (missing: OCAMLFIND OCAML_VERSION OCAML_STDLIB_PATH) 
-- OCaml bindings disabled.
-- LLVM default target triple: x86_64-unknown-linux-gnu
-- Building with -fPIC
-- Targeting AArch64
-- Targeting AMDGPU
-- Targeting ARM
-- Targeting AVR
-- Targeting BPF
-- Targeting Hexagon
-- Targeting Lanai
-- Targeting LoongArch
-- Targeting Mips
-- Targeting MSP430
-- Targeting NVPTX
-- Targeting PowerPC
-- Targeting RISCV
-- Targeting Sparc
-- Targeting SystemZ
-- Targeting VE
-- Targeting WebAssembly
-- Targeting X86
-- Targeting XCore

```

https://github.com/llvm/llvm-project/pull/95411