Arm Compiler for Linux support

[green-br]

Describe the bug When building with the Arm Compiler for Linux CMake complains with:

CMake Warning at cmake/CompilerConfiguration.cmake:39 (message):
  Unknown Fortran compiler, trying without any additional (optimization)
  flags.

  You will most likely have to specify extra options for free-form Fortran
  2008 for your compiler!

  Please open an issue at https://github.com/cp2k/dbcsr/issues with the
  reported compiler name and the required flags.
Call Stack (most recent call first):
  CMakeLists.txt:340 (include)


-- CMAKE_Fortran_COMPILER_ID: Flang

To Reproduce Steps to reproduce the behavior:

1. Built with the command: 'spack install [email protected] %[email protected]'
2. Run like this: (build-only failure)
3. On the architecture/host/platform: 'aarch64, Nvidia Grace CPU Superchip, SLES15sp5'
4. See error

Expected behavior I expect CMake to detect the compiler and use the appropriate flags. Likely to be similar to LLVMFlang (but -std is not an option from look of manual):

set(CMAKE_Fortran_FLAGS          "${CMAKE_Fortran_FLAGS} -ffree-form -cpp")
set(CMAKE_Fortran_FLAGS_RELEASE  "-O3")
set(CMAKE_Fortran_FLAGS_DEBUG    "-O0 -g")

Environment:

• Operating system & version - SLES15sp5
• Compiler vendor & version - Arm Compiler for Linux 24.10
• Build environment (make or cmake) - cmake
• Configuration of DBCSR (either the cmake flags or the Makefile.inc) - generated by Spack for CP2K install.
• MPI implementation and version - OpenMPI 5.0.8
• If CUDA is being used: CUDA version and GPU architecture - not used
• BLAS/LAPACK implementation and version - in-built into Arm Compiler for Linux
• If applicable: Runtime information (how many nodes, type of nodes, ...)