More FindMPI and try_compile() CMake modernization

A bunch of the variable manipulation should be abstracted as a
function.

Author: zbeekman

CMakeLists.txt

@@ -139,6 +139,9 @@ endif()
 if(NOT CMAKE_REQUIRED_FLAGS)
   set(CMAKE_REQUIRED_FLAGS "")
 endif()
+if(NOT CMAKE_REQUIRED_DEFINITIONS)
+  set(CMAKE_REQUIRED_DEFINITIONS "")
+endif()
 if(NOT CMAKE_REQUIRED_LIBRARIES)
   set(CMAKE_REQUIRED_LIBRARIES "")
 endif()
@@ -403,7 +406,9 @@ endif()
 # Make sure a simple "hello world" C mpi program compiles
 #--------------------------------------------------------
 set(OLD_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS})
-set(CMAKE_REQUIRED_FLAGS ${MPI_C_COMPILE_OPTIONS} ${MPI_C_COMPILE_DEFINITIONS} ${MPI_C_LINK_FLAGS})
+set(CMAKE_REQUIRED_FLAGS ${MPI_C_COMPILE_OPTIONS} ${MPI_C_LINK_FLAGS})
+set(OLD_REQUIRED_DEFINITIONS ${CMAKE_REQUIRED_DEFINITIONS})
+set(CMAKE_REQUIRED_DEFINITIONS ${MPI_C_COMPILE_DEFINITIONS})
 set(OLD_INCLUDES ${CMAKE_REQUIRED_INCLUDES})
 set(CMAKE_REQUIRED_INCLUDES ${MPI_C_INCLUDE_DIRS})
 set(OLD_LIBRARIES ${CMAKE_REQUIRED_LIBRARIES})
@@ -427,6 +432,7 @@ int main(int argc, char** argv) {
 }"
 MPI_C_COMPILES)
 set(CMAKE_REQUIRED_FLAGS ${OLD_REQUIRED_FLAGS})
+set(CMAKE_REQUIRED_DEFINITIONS ${OLD_REQUIRED_DEFINITIONS})
 set(CMAKE_REQUIRED_INCLUDES ${OLD_INCLUDES})
 set(CMAKE_REQUIRED_LIBRARIES ${OLD_LIBRARIES})
 unset(OLD_REQUIRED_FLAGS)
@@ -446,7 +452,9 @@ endif()
 # Try using mpi.mod first then fall back on includ 'mpif.h'
 #--------------------------------------------------------------
 set(OLD_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS})
-set(CMAKE_REQUIRED_FLAGS "-ffree-form" ${MPI_Fortran_COMPILE_OPTIONS} ${MPI_Fortran_COMPILE_DEFINITIONS} ${MPI_Fortran_LINK_FLAGS})
+set(CMAKE_REQUIRED_FLAGS "-ffree-form" ${MPI_Fortran_COMPILE_OPTIONS} ${MPI_Fortran_LINK_FLAGS})
+set(OLD_REQUIRED_DEFINITIONS ${CMAKE_REQUIRED_DEFINITIONS})
+set(CMAKE_REQUIRED_DEFINITIONS ${MPI_Fortran_COMPILE_DEFINITIONS})
 set(OLD_INCLUDES ${CMAKE_REQUIRED_INCLUDES})
 set(CMAKE_REQUIRED_INCLUDES ${MPI_Fortran_INCLUDE_DIRS})
 set(OLD_LIBRARIES ${CMAKE_REQUIRED_LIBRARIES})
@@ -468,6 +476,7 @@ end program
 "
 MPI_Fortran_MODULE_COMPILES)
 set(CMAKE_REQUIRED_FLAGS ${OLD_REQUIRED_FLAGS})
+set(CMAKE_REQUIRED_DEFINITIONS ${OLD_REQUIRED_DEFINITIONS})
 set(CMAKE_REQUIRED_INCLUDES ${OLD_INCLUDES})
 set(CMAKE_REQUIRED_LIBRARIES ${OLD_LIBRARIES})
 unset(OLD_REQUIRED_FLAGS)
@@ -478,7 +487,9 @@ unset(OLD_LIBRARIES)
 # If that failed try using mpif.h
 #--------------------------------
 set(OLD_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS})
-set(CMAKE_REQUIRED_FLAGS "-ffree-form" ${MPI_Fortran_COMPILE_OPTIONS} ${MPI_Fortra_COMPILE_DEFINITIONS} ${MPI_Fortran_LINK_FLAGS})
+set(CMAKE_REQUIRED_FLAGS "-ffree-form" ${MPI_Fortran_COMPILE_OPTIONS} ${MPI_Fortran_LINK_FLAGS})
+set(OLD_REQUIRED_DEFINITIONS ${CMAKE_REQUIRED_DEFINITIONS})
+set(CMAKE_REQUIRED_DEFINITIONS ${MPI_Fortra_COMPILE_DEFINITIONS})
 set(OLD_INCLUDES ${CMAKE_REQUIRED_INCLUDES})
 set(CMAKE_REQUIRED_INCLUDES ${MPI_Fortran_INCLUDE_DIRS})
 set(OLD_LIBRARIES ${CMAKE_REQUIRED_LIBRARIES})
@@ -500,6 +511,7 @@ end program
 "
   MPI_Fortran_INCLUDE_COMPILES)
 set(CMAKE_REQUIRED_FLAGS ${OLD_REQUIRED_FLAGS})
+set(CMAKE_REQUIRED_DEFINITIONS ${OLD_REQUIRED_DEFINITIONS})
 set(CMAKE_REQUIRED_INCLUDES ${OLD_INCLUDES})
 set(CMAKE_REQUIRED_LIBRARIES ${OLD_LIBRARIES})
 unset(OLD_REQUIRED_FLAGS)

src/mpi/CMakeLists.txt

@@ -2,6 +2,9 @@
 if(NOT CMAKE_REQUIRED_FLAGS)
   set(CMAKE_REQUIRED_FLAGS "")
 endif()
+if(NOT CMAKE_REQUIRED_DEFINITIONS)
+  set(CMAKE_REQUIRED_DEFINITIONS "")
+endif()
 if(NOT CMAKE_REQUIRED_LIBRARIES)
   set(CMAKE_REQUIRED_LIBRARIES "")
 endif()