Add SYSTEM property for some include directories

We don't need warnings for 3rd-party headers.

Author: dg0yt

3rd-party/clipper/CMakeLists.txt

@@ -120,6 +120,6 @@ set_source_files_properties(${CLIPPER_SOURCES} PROPERTIES GENERATED TRUE)
 
 add_library(polyclipping STATIC ${CLIPPER_SOURCES})
 
-target_include_directories(polyclipping  PUBLIC ${SOURCE_DIR}/cpp)
+target_include_directories(polyclipping SYSTEM PUBLIC ${SOURCE_DIR}/cpp)
 
 add_dependencies(polyclipping Clipper)

3rd-party/qtsingleapplication/CMakeLists.txt

@@ -34,6 +34,7 @@ add_library(QtSingleApplication STATIC
 )
 
 target_include_directories(QtSingleApplication
+  SYSTEM
   INTERFACE "${CMAKE_CURRENT_SOURCE_DIR}/src"
 )
 

src/CMakeLists.txt

@@ -343,5 +343,5 @@ foreach(module ${PRIVATE_MODULES})
 			endif()
 		endforeach()
 	endif()
-	target_include_directories(Mapper_Common PRIVATE ${${qt5_module}_PRIVATE_INCLUDE_DIRS})
+	target_include_directories(Mapper_Common SYSTEM PRIVATE ${${qt5_module}_PRIVATE_INCLUDE_DIRS})
 endforeach()

src/gdal/CMakeLists.txt

@@ -47,7 +47,8 @@ target_compile_definitions(mapper-gdal PRIVATE
 
 target_compile_definitions(mapper-gdal INTERFACE MAPPER_USE_GDAL)
 
-target_include_directories(mapper-gdal PRIVATE "${GDAL_INCLUDE_DIR}" "${PROJECT_SOURCE_DIR}/src")
+target_include_directories(mapper-gdal SYSTEM PRIVATE "${GDAL_INCLUDE_DIR}")
+target_include_directories(mapper-gdal PRIVATE "${PROJECT_SOURCE_DIR}/src")
 
 target_link_libraries(mapper-gdal "${GDAL_LIBRARY}" Qt5::Core Qt5::Gui Qt5::Widgets)
 

src/printsupport/CMakeLists.txt

@@ -51,7 +51,9 @@ target_compile_definitions(printsupport PRIVATE
   QT_USE_QSTRINGBUILDER
 )
 target_include_directories(printsupport
-  BEFORE PRIVATE "${CMAKE_CURRENT_SOURCE_DIR}/${FORK_VERSION}"
+  SYSTEM
+  BEFORE
+  PRIVATE "${CMAKE_CURRENT_SOURCE_DIR}/${FORK_VERSION}"
   INTERFACE "${CMAKE_CURRENT_SOURCE_DIR}"
 )
 
@@ -75,5 +77,5 @@ foreach(module Core Gui PrintSupport)
 			endif()
 		endforeach()
 	endif()
-	target_include_directories(printsupport PRIVATE ${${qt5_module}_PRIVATE_INCLUDE_DIRS})
+	target_include_directories(printsupport SYSTEM PRIVATE ${${qt5_module}_PRIVATE_INCLUDE_DIRS})
 endforeach()