re-enabled support for older CMake

CMakeLists.txt

@@ -29,7 +29,7 @@ else()
 endif()
 add_definitions("-D${DAMASK_SOLVER}")
 
-set(CMAKE_Fortran_PREPROCESS "ON")
+set(CMAKE_Fortran_PREPROCESS "ON") # works only for CMake >= 3.18
 
 # EXPERIMENTAL: This might help to detect HDF5 and FFTW3 in the future if PETSc is not aware of them
 set(ENV{PKG_CONFIG_PATH} "$ENV{PETSC_DIR}/$ENV{PETSC_ARCH}/externalpackages:$ENV{PKG_CONFIG_PATH}")

cmake/Compiler-GNU.cmake

@@ -19,6 +19,8 @@ set (STANDARD_CHECK "-std=f2018 -pedantic-errors" )
 
 #------------------------------------------------------------------------------------------------
 # Fine tuning compilation options
+set (COMPILE_FLAGS "${COMPILE_FLAGS} -cpp") # preprocessor, needed for CMake < 3.18
+
 set (COMPILE_FLAGS "${COMPILE_FLAGS} -fPIE")
 # position independent code
 

cmake/Compiler-Intel.cmake

@@ -22,6 +22,8 @@ set (LINKER_FLAGS   "${LINKER_FLAGS} -shared-intel")
 
 #------------------------------------------------------------------------------------------------
 # Fine tuning compilation options
+set (COMPILE_FLAGS "${COMPILE_FLAGS} -fpp") # preprocessor, needed for CMake < 3.18
+
 set (COMPILE_FLAGS "${COMPILE_FLAGS} -no-ftz")
 # disable flush underflow to zero, will be set if -O[1,2,3]
 

cmake/Compiler-IntelLLVM.cmake

@@ -24,6 +24,8 @@ set (LINKER_FLAGS   "${LINKER_FLAGS} -shared-intel -fc=ifx")
 
 #------------------------------------------------------------------------------------------------
 # Fine tuning compilation options
+set (COMPILE_FLAGS "${COMPILE_FLAGS} -fpp") # preprocessor, needed for CMake < 3.18
+
 set (COMPILE_FLAGS "${COMPILE_FLAGS} -no-ftz")
 # disable flush underflow to zero, will be set if -O[1,2,3]
 

cmake/Compiler-LLVMFlang.cmake

@@ -9,4 +9,4 @@ set (STANDARD_CHECK "-std=f2018 -pedantic" )
 
 #------------------------------------------------------------------------------------------------
 # Fine tuning compilation options
-
+set (COMPILE_FLAGS "${COMPILE_FLAGS} -cpp") # preprocessor, needed for CMake < 3.18