improve install support for enkiTS (#96)

CMakeLists.txt

@@ -2,6 +2,8 @@ cmake_minimum_required(VERSION 3.0)
 
 project( enkiTS )
 
+include(GNUInstallDirs)
+
 option( ENKITS_BUILD_C_INTERFACE    "Build C interface" ON )
 option( ENKITS_BUILD_EXAMPLES       "Build example applications" ON )
 option( ENKITS_BUILD_SHARED         "Build shared library" OFF )
@@ -43,7 +45,9 @@ else()
     add_library( enkiTS STATIC ${ENKITS_SRC} )
 endif()
 
-target_include_directories( enkiTS PUBLIC "${PROJECT_SOURCE_DIR}/src")
+target_include_directories( enkiTS PUBLIC
+    PUBLIC $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/src>
+           $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}> )
 
 if( ENKITS_TASK_PRIORITIES_NUM GREATER "0" )
     target_compile_definitions( enkiTS PUBLIC "ENKITS_TASK_PRIORITIES_NUM=${ENKITS_TASK_PRIORITIES_NUM}" )
@@ -59,8 +63,15 @@ if( UNIX )
 endif()
 
 if( ENKITS_INSTALL )
-    install(TARGETS enkiTS DESTINATION "${CMAKE_INSTALL_PREFIX}/lib/enkiTS")
-    install(FILES ${ENKITS_HEADERS} DESTINATION "${CMAKE_INSTALL_PREFIX}/include/enkiTS")
+    install(
+        TARGETS enkiTS
+        EXPORT enkiTS-config
+        ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR})
+    install(FILES ${ENKITS_HEADERS} DESTINATION ${CMAKE_INSTALL_INCLUDEDIR})
+    install(
+        EXPORT enkiTS-config
+        NAMESPACE enkiTS::
+        DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/enkiTS)
 endif()
 
 if( UNIX )