CMake: Fix non-existing target warnings

Author: lukas-w

CMakeLists.txt

@@ -9,6 +9,7 @@ IF(COMMAND CMAKE_POLICY)
 	CMAKE_POLICY(SET CMP0003 NEW)
 	IF (CMAKE_MAJOR_VERSION GREATER 2)
 		CMAKE_POLICY(SET CMP0026 OLD)
+		CMAKE_POLICY(SET CMP0045 NEW)
 		CMAKE_POLICY(SET CMP0050 OLD)
 	ENDIF()
 ENDIF(COMMAND CMAKE_POLICY)

src/CMakeLists.txt

@@ -160,9 +160,11 @@ TARGET_LINK_LIBRARIES(lmms
 )
 
 FOREACH(LIB ${LMMS_REQUIRED_LIBS})
-    GET_TARGET_PROPERTY(INCLUDE_DIRS ${LIB} INTERFACE_INCLUDE_DIRECTORIES)
-    if (INCLUDE_DIRS)
-        TARGET_INCLUDE_DIRECTORIES(lmmsobjs PRIVATE ${INCLUDE_DIRS})
+	IF(TARGET ${LIB})
+	    GET_TARGET_PROPERTY(INCLUDE_DIRS ${LIB} INTERFACE_INCLUDE_DIRECTORIES)
+	    if (INCLUDE_DIRS)
+	        TARGET_INCLUDE_DIRECTORIES(lmmsobjs PRIVATE ${INCLUDE_DIRS})
+	    ENDIF()
     ENDIF()
 ENDFOREACH()