cmake: Allow C++17 mode on all platforms, all modules.

Remove per-module C++17 settings.

CMakeLists.txt

@@ -1,4 +1,4 @@
-# Copyright 2018-2020, Collabora, Ltd.
+# Copyright 2018-2021, Collabora, Ltd.
 # SPDX-License-Identifier: BSL-1.0
 
 cmake_minimum_required(VERSION 3.10.2)
@@ -12,6 +12,10 @@ endif()
 option(XRT_OPENXR_INSTALL_ABSOLUTE_RUNTIME_PATH "Use the absolute path to the runtime in the installed manifest, rather than a bare filename." ON)
 option(XRT_OPENXR_INSTALL_ACTIVE_RUNTIME "Make Monado the default OpenXR runtime on install" ON)
 
+# We use C++17
+set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+
 ###
 # Dependencies
 ###

doc/changes/misc_features/mr.809.md

@@ -0,0 +1 @@
+For code that is implemented in C++, note that the default standard mode is now C++17 across all platforms and modules, instead of a mix of 14 and 17 like before. The CI remains the decider of what functionality is available, as it contains the oldest distribution we support (Debian Buster).

src/external/CMakeLists.txt

@@ -40,10 +40,6 @@ if(ANDROID)
 		${WRAP_SOURCES})
 	target_include_directories(xrt-external-jni-wrap PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/android-jni-wrap)
 	target_link_libraries(xrt-external-jni-wrap PUBLIC xrt-external-jnipp)
-	set_target_properties(xrt-external-jni-wrap
-		PROPERTIES
-		CXX_STANDARD 17
-		CXX_STANDARD_REQUIRED ON)
 endif()
 
 # OpenXR

src/xrt/auxiliary/CMakeLists.txt

@@ -304,10 +304,6 @@ if(ANDROID)
 		PUBLIC aux_util
 		PRIVATE ${ANDROID_LIBRARY} ${ANDROID_LOG_LIBRARY} xrt-external-jni-wrap xrt-external-jnipp
 		)
-	set_target_properties(aux_android
-		PROPERTIES
-		CXX_STANDARD 17
-		CXX_STANDARD_REQUIRED ON)
 	target_link_libraries(aux_vk PUBLIC aux_android)
 endif()
 

src/xrt/drivers/CMakeLists.txt

@@ -276,7 +276,6 @@ if (XRT_BUILD_DRIVER_ILLIXR)
 	add_library(drv_illixr STATIC ${ILLIXR_SOURCE_FILES})
 	target_link_libraries(drv_illixr PUBLIC ${CMAKE_DL_LIBS} xrt-interfaces aux_util aux_os)
 	target_include_directories(drv_illixr PUBLIC ${ILLIXR_PATH})
-	target_compile_options(drv_illixr PUBLIC $<$<COMPILE_LANGUAGE:CXX>:-std=c++17>)
 	list(APPEND ENABLED_HEADSET_DRIVERS illixr)
 endif()
 

src/xrt/ipc/CMakeLists.txt

@@ -110,10 +110,6 @@ if(ANDROID)
 		xrt-external-jnipp
 		aux_android
 		)
-	set_target_properties(ipc_android
-		PROPERTIES
-		CXX_STANDARD 17
-		CXX_STANDARD_REQUIRED ON)
 	target_sources(ipc_server PRIVATE
 		${CMAKE_CURRENT_SOURCE_DIR}/server/ipc_server_mainloop_android.c
 		)

src/xrt/targets/service-lib/CMakeLists.txt

@@ -15,8 +15,3 @@ target_link_libraries(monado-service PRIVATE
 	target_instance
 	xrt-external-jni-wrap
 	)
-
-set_target_properties(monado-service
-	PROPERTIES
-	CXX_STANDARD 17
-	CXX_STANDARD_REQUIRED ON)