Add LFortran as compiler to build options

Provides the necessary changes to use LFortran as the compiler for
this project to the extend that it currently can. Please note the
corresponding issue to gain further information on how to use this.
It provides a compilation script and references the required mpi
wrapper library.

Author: keyvizsla

cmake/SetBuildOptions.cmake

@@ -12,12 +12,12 @@ endif()
 
 # Check if MPI is present. This should succeed if
 # the compilers were set to mpifort and mpicc.
-find_package(MPI REQUIRED)
 
 # Set default compiler = GNU if none was specified. 
 if(NOT COMPILER)
     set(COMPILER "${CMAKE_Fortran_COMPILER_ID}" CACHE STRING "Choose compiler toolchain." FORCE)
     set_property(CACHE COMPILER PROPERTY STRINGS "GNU" "Intel")
+    set_property(CACHE COMPILER PROPERTY STRINGS "GNU" "Intel" "LFortran")
 endif()
 
 # Set compiler specific flags.
@@ -44,6 +44,11 @@ elseif(COMPILER STREQUAL "Intel" OR COMPILER STREQUAL "IntelLLVM")
       set(CMAKE_Fortran_FLAGS_DEBUG "-O0 -g -fpe0 -check all")
     endif()
     set(CMAKE_Fortran_FLAGS_RELEASE "-O2 -debug minimal")
+elseif(COMPILER STREQUAL "LFortran")
+    add_compile_definitions(CPRLFORTRAN)
+    # There is an issue, some modules require --cpp as a flag in their compilation
+    # some flat out break, if we put --cpp
+    # set(CMAKE_Fortran_FLAGS "--cpp")
 else()
     message(FATAL_ERROR "COMPILER='${COMPILER}' is not supported.")
 endif()

src/externals/gptl/CMakeLists.txt

@@ -9,7 +9,7 @@ SET(TIMING_INCLUDE_DIRS   ${CMAKE_CURRENT_SOURCE_DIR}
     CACHE STRING "")
 INCLUDE_DIRECTORIES(${TIMING_INCLUDE_DIRS})
 
-ADD_DEFINITIONS(-DINCLUDE_CMAKE_FCI -DHAVE_MPI)
+ADD_DEFINITIONS(-DINCLUDE_CMAKE_FCI)
 
 SET(SRCS_C  GPTLget_memusage.c
             GPTLprint_memusage.c

src/externals/gptl/Makefile

@@ -32,7 +32,6 @@ ifeq ($(strip $(MPILIB)), mpi-serial)
 else
   CC := $(MPICC)
   FC := $(MPIFC)
-  CPPDEFS += -DHAVE_MPI
 endif
 ifdef CPRE
   FPPDEFS := $(patsubst -D%,$(CPRE)%,$(CPPDEFS))

src/externals/gptl/perf_utils.F90

@@ -164,9 +164,6 @@ SUBROUTINE shr_sys_flush(unit)
    call flush(unit)
 #endif
 #endif
-#if (defined AIX)
-   call flush_(unit)
-#endif
 
 END SUBROUTINE shr_sys_flush