Make sure the third-party libraries are always included as "system".

dependencies/CMakeLists.txt

@@ -60,7 +60,7 @@ find_package(Intl REQUIRED)
 add_library(app_gettext_interface INTERFACE)
 if (Intl_INCLUDE_DIRS)
 	target_include_directories(app_gettext_interface
-		INTERFACE
+		SYSTEM INTERFACE
 			${Intl_INCLUDE_DIRS}
 	)
 endif()

dependencies/catch2/CMakeLists.txt

@@ -15,7 +15,7 @@ target_sources(Catch2 INTERFACE
 )
 
 target_include_directories(Catch2
-	INTERFACE SYSTEM
+	SYSTEM INTERFACE
 		"${CMAKE_SOURCE_DIR}/dependencies/catch2/Catch2/single_include"
 )
 

dependencies/leaf/CMakeLists.txt

@@ -13,7 +13,7 @@ target_sources(boost_leaf INTERFACE
 )
 
 target_include_directories(boost_leaf
-	INTERFACE SYSTEM
+	SYSTEM INTERFACE
 		"${CMAKE_SOURCE_DIR}/dependencies/leaf/standalone"
 		"${CMAKE_SOURCE_DIR}/dependencies/leaf/convenience"
 )

dependencies/nlohmann_json/CMakeLists.txt

@@ -12,7 +12,7 @@ target_sources(nlohmann_json INTERFACE
 )
 
 target_include_directories(nlohmann_json
-	INTERFACE SYSTEM
+	SYSTEM INTERFACE
 		"${CMAKE_SOURCE_DIR}/dependencies/nlohmann_json"
 )
 

dependencies/whereami/CMakeLists.txt

@@ -12,7 +12,7 @@ target_sources(whereami PRIVATE
 )
 
 target_include_directories(whereami
-	PUBLIC
+	SYSTEM PUBLIC
 		"${CMAKE_CURRENT_SOURCE_DIR}/whereami/src"
 )