Normalize installation structure to match GNU

 Fixes #79

 - Use the CMake GNUInstallDirs module to help locate where to put
   stuff
 - Install library header files too
 - Put module into include, but also namespace it with compiler ID and version

 Directory structure looks like this:

 ```
/usr/local/Cellar/OpenCoarrays/1.8.3
├── bin
│   ├── caf
│   └── cafrun
├── include
│   ├── OpenCoarrays
│   │   └── GNU
│   │       └── 6.3.0
│   │           └── opencoarrays.mod
│   ├── libcaf-gfortran-descriptor.h
│   ├── libcaf.h
│   └── opencoarrays.mod -> /usr/local/Cellar/OpenCoarrays/1.8.3/include/OpenCoarrays/GNU/6.3.0/opencoarrays.mod
└── lib
    ├── cmake
    │   └── opencoarrays
    │       ├── OpenCoarraysConfig.cmake
    │       ├── OpenCoarraysConfigVersion.cmake
    │       ├── OpenCoarraysTargets-release.cmake
    │       └── OpenCoarraysTargets.cmake
    └── libcaf_mpi.a

8 directories, 11 files
 ```

Author: zbeekman

CMakeLists.txt

@@ -290,6 +290,11 @@ set(CMAKE_Fortran_COMPILE_FLAGS ${CMAKE_Fortran_COMPILE_FLAGS} ${MPI_Fortran_COM
 set(CMAKE_Fortran_LINK_FLAGS ${CMAKE_Fortran_LINK_FLAGS} ${MPI_Fortran_LINK_FLAGS})
 include_directories(BEFORE ${MPI_C_INCLUDE_PATH} ${MPI_Fortran_INCLUDE_PATH})
 
+#---------------------------------------------------
+# Use standardized GNU install directory conventions
+#---------------------------------------------------
+include(GNUInstallDirs)
+
 #-------------------------------
 # Recurse into the src directory
 #-------------------------------
@@ -304,7 +309,7 @@ install(EXPORT OpenCoarraysTargets
   NAMESPACE
     OpenCoarrays::
   DESTINATION
-    lib/cmake/opencoarrays
+    "${CMAKE_INSTALL_LIBDIR}/cmake/opencoarrays"
 )
 include(CMakePackageConfigHelpers) # standard CMake module
 write_basic_package_version_file(
@@ -320,15 +325,13 @@ install(
     "${CMAKE_CURRENT_BINARY_DIR}/CMakeFiles/OpenCoarraysConfig.cmake"
     "${CMAKE_CURRENT_BINARY_DIR}/OpenCoarraysConfigVersion.cmake"
   DESTINATION
-    lib/cmake/opencoarrays
+    "${CMAKE_INSTALL_LIBDIR}/cmake/opencoarrays"
 )
 
 add_library(OpenCoarrays INTERFACE)
 target_compile_options(OpenCoarrays INTERFACE -fcoarray=lib)
 target_link_libraries(OpenCoarrays INTERFACE caf_mpi)
 
-install(DIRECTORY  ${CMAKE_BINARY_DIR}/mod DESTINATION .)
-
 #------------------------------------------
 # Add portable unistall command to makefile
 #------------------------------------------

src/CMakeLists.txt

@@ -2,3 +2,7 @@ set(directories_to_build mpi tests)
 foreach(directory ${directories_to_build})
   add_subdirectory(${directory})
 endforeach()
+
+install( FILES libcaf.h libcaf-gfortran-descriptor.h
+  DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}"
+)

src/mpi/CMakeLists.txt

@@ -53,10 +53,22 @@ endif()
 include_directories(${CMAKE_BINARY_DIR}/mod)
 
 install(TARGETS caf_mpi EXPORT OpenCoarraysTargets
-  ARCHIVE DESTINATION lib
-  LIBRARY DESTINATION lib
+  ARCHIVE DESTINATION "${CMAKE_INSTALL_LIBDIR}"
+  LIBRARY DESTINATION "${CMAKE_INSTALL_LIBDIR}"
 )
-install(DIRECTORY  ${CMAKE_BINARY_DIR}/mod DESTINATION .)
+
+# Install modules to standard include dir, but namespace them with compiler/version
+set (mod_install "${CMAKE_INSTALL_FULL_INCLUDEDIR}/OpenCoarrays/${CMAKE_Fortran_COMPILER_ID}/${CMAKE_Fortran_COMPILER_VERSION}")
+install(DIRECTORY  "${CMAKE_BINARY_DIR}/mod/"
+  DESTINATION "${mod_install}"
+  FILES_MATCHING PATTERN "*.mod"
+)
+
+# Now add a link in standard include dir so that compilers will find by default... this may or may not actually be a good idea...
+if ( "${CMAKE_Fortran_COMPILER_ID}" MATCHES "GNU" )
+  INSTALL(CODE "execute_process( COMMAND ${CMAKE_COMMAND} -E create_symlink ${mod_install}/opencoarrays.mod ${CMAKE_INSTALL_FULL_INCLUDEDIR}/opencoarrays.mod )"
+  )
+endif ()
 
 # Now we write the script that passes CAF source to the compiler with the necessary arguments
 # and, if necessary, performs some code transformations prior to invoking the compiler.
@@ -65,12 +77,12 @@ set(compiler_wrapper ${exe_dir}/caf)
 install(
     FILES "${compiler_wrapper}"
     PERMISSIONS WORLD_EXECUTE WORLD_READ WORLD_WRITE OWNER_EXECUTE OWNER_READ OWNER_WRITE GROUP_EXECUTE GROUP_READ GROUP_WRITE
-    DESTINATION ${CMAKE_INSTALL_PREFIX}/bin/
+    DESTINATION "${CMAKE_INSTALL_BINDIR}"
 )
 file(READ ${CMAKE_CURRENT_SOURCE_DIR}/../extensions/caf-head CAF_HEADER)
 file(WRITE  "${compiler_wrapper}" "${CAF_HEADER}\n")
-file(APPEND "${compiler_wrapper}"  "caf_mod_dir=${CMAKE_INSTALL_PREFIX}/mod\n")
-file(APPEND "${compiler_wrapper}"  "caf_lib_dir=${CMAKE_INSTALL_PREFIX}/lib\n")
+file(APPEND "${compiler_wrapper}"  "caf_mod_dir=\"${CMAKE_INSTALL_INCLUDEDIR}/mod\"\n")
+file(APPEND "${compiler_wrapper}"  "caf_lib_dir=\"${CMAKE_INSTALL_LIBDIR}\"\n")
 file(APPEND "${compiler_wrapper}"  "caf_version=${PROJECT_VERSION}\n")
 if(gfortran_compiler)
   file(APPEND "${compiler_wrapper}"  "link_args='-fcoarray=lib -lcaf_mpi'\n")
@@ -98,7 +110,7 @@ set(caf_launcher ${exe_dir}/cafrun)
 install(
     FILES "${caf_launcher}"
     PERMISSIONS WORLD_EXECUTE WORLD_READ WORLD_WRITE OWNER_EXECUTE OWNER_READ OWNER_WRITE GROUP_EXECUTE GROUP_READ GROUP_WRITE
-    DESTINATION ${CMAKE_INSTALL_PREFIX}/bin
+    DESTINATION "${CMAKE_INSTALL_BINDIR}"
 )
 file(READ ${CMAKE_CURRENT_SOURCE_DIR}/../extensions/cafrun-head CAFRUN_HEADER)
 file(WRITE  "${caf_launcher}" "${CAFRUN_HEADER}\n")

src/single/CMakeLists.txt

@@ -1,5 +1,5 @@
 add_library(caf_single single.c ../common/caf_auxiliary.c)
 target_compile_options(caf_single INTERFACE -fcoarray=lib)
 install(TARGETS caf_single EXPORT OpenCoarraysTargets
-  ARCHIVE DESTINATION lib
+  ARCHIVE DESTINATION "${CMAKE_INSTALL_LIBDIR}"
 )