Drop cmake anti-pattern (!101)

This removes an anti-pattern from `CMakeLists.txt` (I'm very sorry for introducing it). The most annoying part about it is that it makes it difficult for a parent project (e.g. ICON) to support multi-configuration backends properly. Basically, the only right place to set `CMAKE_BUILD_TYPE` is on the command line when calling `cmake` (and generating for a single-configuration backend). Also, see [here](https://stackoverflow.com/questions/24460486/cmake-build-type-is-not-being-used-in-cmakelists-txt/24470998#24470998

).

Approved-by: Yen-Chen Chen <yen-chen.chen@kit.edu>
Merged-by: Yen-Chen Chen <yen-chen.chen@kit.edu>
Changelog: bugfix

.gitlab-ci.yml

@@ -47,7 +47,7 @@ nag:
     - export NAG_KUSARI_FILE="/etc/nag-license"
     - mkdir nag71
     - cd nag71
-    - /sw/spack-levante/cmake-3.23.1-q5kzz6/bin/cmake ..  -DCMAKE_C_COMPILER=gcc -DCMAKE_Fortran_COMPILER=nagfor -DCMAKE_CXX_COMPILER=g++ -DCMAKE_BUILD_RPATH=/sw/spack-levante/gcc-11.2.0-bcn7mb/lib64
+    - /sw/spack-levante/cmake-3.23.1-q5kzz6/bin/cmake .. -DCMAKE_BUILD_TYPE=RelWithDebInfo -DCMAKE_C_COMPILER=gcc -DCMAKE_Fortran_COMPILER=nagfor -DCMAKE_CXX_COMPILER=g++ -DCMAKE_BUILD_RPATH=/sw/spack-levante/gcc-11.2.0-bcn7mb/lib64
     - make VERBOSE=1
     - ctest --output-on-failure
   tags:
@@ -64,7 +64,7 @@ gcc11:
     - module load gcc/11.2.0-gcc-11.2.0
     - mkdir gcc112
     - cd gcc112
-    - /sw/spack-levante/cmake-3.23.1-q5kzz6/bin/cmake ..  -DCMAKE_C_COMPILER=gcc -DCMAKE_Fortran_COMPILER=gfortran -DCMAKE_CXX_COMPILER=g++
+    - /sw/spack-levante/cmake-3.23.1-q5kzz6/bin/cmake .. -DCMAKE_BUILD_TYPE=RelWithDebInfo -DCMAKE_C_COMPILER=gcc -DCMAKE_Fortran_COMPILER=gfortran -DCMAKE_CXX_COMPILER=g++
     - make VERBOSE=1
     - ctest --output-on-failure
   tags:
@@ -81,7 +81,7 @@ intel22:
     - module load gcc/11.2.0-gcc-11.2.0 intel-oneapi-compilers/2022.0.1-gcc-11.2.0
     - mkdir intel22
     - cd intel22
-    - /sw/spack-levante/cmake-3.23.1-q5kzz6/bin/cmake ..  -DCMAKE_C_COMPILER=icc -DCMAKE_Fortran_COMPILER=ifort -DCMAKE_CXX_COMPILER=icpc -DCMAKE_BUILD_RPATH=/sw/spack-levante/gcc-11.2.0-bcn7mb/lib64
+    - /sw/spack-levante/cmake-3.23.1-q5kzz6/bin/cmake .. -DCMAKE_BUILD_TYPE=RelWithDebInfo -DCMAKE_C_COMPILER=icc -DCMAKE_Fortran_COMPILER=ifort -DCMAKE_CXX_COMPILER=icpc -DCMAKE_BUILD_RPATH=/sw/spack-levante/gcc-11.2.0-bcn7mb/lib64
     - make VERBOSE=1
     - ctest --output-on-failure
   tags:
@@ -98,7 +98,7 @@ nvhpc:
     - module load gcc/11.2.0-gcc-11.2.0 nvhpc/22.5-gcc-11.2.0
     - mkdir nvhpc
     - cd nvhpc
-    - /sw/spack-levante/cmake-3.23.1-q5kzz6/bin/cmake ..  -DCMAKE_C_COMPILER=nvc -DCMAKE_Fortran_COMPILER=nvfortran -DCMAKE_CXX_COMPILER=nvc++
+    - /sw/spack-levante/cmake-3.23.1-q5kzz6/bin/cmake .. -DCMAKE_BUILD_TYPE=RelWithDebInfo -DCMAKE_C_COMPILER=nvc -DCMAKE_Fortran_COMPILER=nvfortran -DCMAKE_CXX_COMPILER=nvc++
     - make VERBOSE=1
     - ctest --output-on-failure
   tags:
@@ -115,7 +115,7 @@ OpenACC:
     - module load gcc/11.2.0-gcc-11.2.0 nvhpc/22.5-gcc-11.2.0
     - mkdir nvhpc
     - cd nvhpc
-    - /sw/spack-levante/cmake-3.23.1-q5kzz6/bin/cmake .. -DFS_ENABLE_OPENACC=ON  -DCMAKE_C_COMPILER=nvc -DCMAKE_Fortran_COMPILER=nvfortran -DCMAKE_CXX_COMPILER=nvc++
+    - /sw/spack-levante/cmake-3.23.1-q5kzz6/bin/cmake .. -DCMAKE_BUILD_TYPE=RelWithDebInfo -DFS_ENABLE_OPENACC=ON  -DCMAKE_C_COMPILER=nvc -DCMAKE_Fortran_COMPILER=nvfortran -DCMAKE_CXX_COMPILER=nvc++
     - make VERBOSE=1
   tags:
     - levante, hpc, dkrz

CMakeLists.txt

@@ -24,17 +24,6 @@ option(FS_ENABLE_OMP "Build with OpenMP support" OFF)
 option(FS_ENABLE_OPENACC "Build with OpenACC support" OFF)
 option(FS_ENABLE_MIXED_PRECISION "Use mixed precision" OFF)
 
-if(NOT CMAKE_BUILD_TYPE)
-  set(CMAKE_BUILD_TYPE
-      "RelWithDebInfo"
-      CACHE
-        STRING
-        "Choose the type of build, options are: Debug Release RelWithDebInfo"
-        FORCE)
-  message(
-    STATUS "Setting build type to '${CMAKE_BUILD_TYPE}' as none was specified")
-endif(NOT CMAKE_BUILD_TYPE)
-
 include(GNUInstallDirs)
 
 add_subdirectory(src)