Allow modification of install directory for module files

Author: awvwgk

config/CMakeLists.txt

@@ -1,5 +1,11 @@
 # SPDX-Identifier: MIT
 
+option(
+  CMAKE_INSTALL_MODULEDIR
+  "Directory in prefix to install generated module files"
+  "${CMAKE_INSTALL_INCLUDEDIR}/${PROJECT_NAME}/${CMAKE_Fortran_COMPILER_ID}-${CMAKE_Fortran_COMPILER_VERSION}"
+)
+
 # Export a pkg-config file
 configure_file(
   "${CMAKE_CURRENT_SOURCE_DIR}/template.pc"

config/template.pc

@@ -1,9 +1,10 @@
 prefix=@CMAKE_INSTALL_PREFIX@
 libdir=${prefix}/@CMAKE_INSTALL_LIBDIR@
 includedir=${prefix}/@CMAKE_INSTALL_INCLUDEDIR@
+moduledir=${prefix}/@CMAKE_INSTALL_MODULEDIR@
 
 Name: @PROJECT_NAME@
 Description: @PROJECT_DESCRIPTION@
 Version: @PROJECT_VERSION@
 Libs: -L${libdir} -l@PROJECT_NAME@
-Cflags: -I${includedir}
+Cflags: -I${includedir} -I${moduledir}

src/CMakeLists.txt

@@ -55,7 +55,7 @@ set_target_properties(${PROJECT_NAME} PROPERTIES
     Fortran_MODULE_DIRECTORY ${LIB_MOD_DIR})
 target_include_directories(${PROJECT_NAME} PUBLIC
     $<BUILD_INTERFACE:${LIB_MOD_DIR}>
-    $<INSTALL_INTERFACE:include>
+    $<INSTALL_INTERFACE:${CMAKE_INSTALL_MODULEDIR}>
 )
 
 if(f18errorstop)
@@ -72,4 +72,4 @@ install(TARGETS ${PROJECT_NAME}
         ARCHIVE DESTINATION "${CMAKE_INSTALL_LIBDIR}"
         LIBRARY DESTINATION "${CMAKE_INSTALL_LIBDIR}"
 )
-install(DIRECTORY ${LIB_MOD_DIR} DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}")
+install(DIRECTORY ${LIB_MOD_DIR} DESTINATION "${CMAKE_INSTALL_MODULEDIR}")