SDL + Linux armv7hl use XDisplay by default, without linking X11

[akien-mga]

What happens?

Building PPSSPP 1.7.2 on Mageia 7 armv7hl (with #11538 to make it properly link about libGL.so), I run into the following build issue:

[100%] Linking CXX executable PPSSPPSDL
/usr/bin/cmake -E cmake_link_script CMakeFiles/PPSSPPSDL.dir/link.txt --verbose=1
/usr/bin/c++  -O2 -g -pipe -Wformat -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -march=armv7-a -mfloat-abi=hard -mfpu=vfpv3-d16 -DNDEBUG -O2 -g -D_NDEBUG  -Wl,--as-needed -Wl,--no-undefined -Wl,-z,relro -Wl,-O1 -Wl,--build-id -Wl,--enable-new-dtags CMakeFiles/PPSSPPSDL.dir/android/jni/TestRunner.cpp.o CMakeFiles/PPSSPPSDL.dir/UI/DiscordIntegration.cpp.o CMakeFiles/PPSSPPSDL.dir/UI/NativeApp.cpp.o CMakeFiles/PPSSPPSDL.dir/UI/BackgroundAudio.cpp.o CMakeFiles/PPSSPPSDL.dir/UI/DevScreens.cpp.o CMakeFiles/PPSSPPSDL.dir/UI/DisplayLayoutEditor.cpp.o CMakeFiles/PPSSPPSDL.dir/UI/DisplayLayoutScreen.cpp.o CMakeFiles/PPSSPPSDL.dir/UI/EmuScreen.cpp.o CMakeFiles/PPSSPPSDL.dir/UI/GameInfoCache.cpp.o CMakeFiles/PPSSPPSDL.dir/UI/MainScreen.cpp.o CMakeFiles/PPSSPPSDL.dir/UI/MiscScreens.cpp.o CMakeFiles/PPSSPPSDL.dir/UI/PauseScreen.cpp.o CMakeFiles/PPSSPPSDL.dir/UI/GameScreen.cpp.o CMakeFiles/PPSSPPSDL.dir/UI/GameSettingsScreen.cpp.o CMakeFiles/PPSSPPSDL.dir/UI/TiltAnalogSettingsScreen.cpp.o CMakeFiles/PPSSPPSDL.dir/UI/TiltEventProcessor.cpp.o CMakeFiles/PPSSPPSDL.dir/UI/TouchControlLayoutScreen.cpp.o CMakeFiles/PPSSPPSDL.dir/UI/TouchControlVisibilityScreen.cpp.o CMakeFiles/PPSSPPSDL.dir/UI/GamepadEmu.cpp.o CMakeFiles/PPSSPPSDL.dir/UI/OnScreenDisplay.cpp.o CMakeFiles/PPSSPPSDL.dir/UI/ControlMappingScreen.cpp.o CMakeFiles/PPSSPPSDL.dir/UI/RemoteISOScreen.cpp.o CMakeFiles/PPSSPPSDL.dir/UI/ReportScreen.cpp.o CMakeFiles/PPSSPPSDL.dir/UI/SavedataScreen.cpp.o CMakeFiles/PPSSPPSDL.dir/UI/Store.cpp.o CMakeFiles/PPSSPPSDL.dir/UI/CwCheatScreen.cpp.o CMakeFiles/PPSSPPSDL.dir/UI/InstallZipScreen.cpp.o CMakeFiles/PPSSPPSDL.dir/UI/ProfilerDraw.cpp.o CMakeFiles/PPSSPPSDL.dir/UI/ui_atlas.cpp.o CMakeFiles/PPSSPPSDL.dir/UI/TextureUtil.cpp.o CMakeFiles/PPSSPPSDL.dir/UI/ComboKeyMappingScreen.cpp.o  -o PPSSPPSDL lib/libCore.a -lpthread lib/libCommon.a /lib/libsnappy.so lib/libnative.a /usr/lib/libSDL2.so /usr/lib/libzip.so lib/libpng17.a lib/librg_etc1.a lib/libgason.a lib/libudis86.a -lrt -lpthread /usr/lib/libGLEW.so lib/libkirk.a lib/libcityhash.a lib/libsfmt19937.a lib/libxbrz.a lib/libxxhash.a lib/libSPIRV.a lib/libglslang.a lib/libOGLCompiler.a lib/libOSDependent.a lib/libHLSL.a lib/libSPVRemapper.a lib/libspirv-cross-glsl.a lib/libspirv-cross-core.a lib/libarmips.a /usr/lib/libGL.so /usr/lib/libGLU.so -lEGL -ldl /usr/lib/libavformat.so /usr/lib/libavcodec.so /usr/lib/libswresample.so /usr/lib/libswscale.so /usr/lib/libavutil.so /usr/lib/libz.so lib/libdiscord-rpc.a 
/usr/bin/ld: lib/libnative.a(SDLGLGraphicsContext.cpp.o): undefined reference to symbol 'XOpenDisplay'
/usr/bin/ld: /lib/libX11.so.6: error adding symbols: DSO missing from command line

XOpenDisplay is used in SDL/SDLGLGraphicsContext.cpp by default, unless USING_FBDEV is defined. I'll admit that I'm not familiar with ARM platforms so I don't know if I should be using USING_FBDEV here, but in any case the NOT USING_FBDEV case should likely link against X11 to be able to use XOpenDisplay.

What should happen?

It should link fine out of the box ;)

What hardware, operating system, and PPSSPP version? On desktop, GPU matters for graphical issues.

ARMv7 hl build nodes of Mageia's buildsystem, Mageia 7 (Cauldron).
PPSSPP 1.7.1.

[unknownbrackets]

Perhaps changing:

if(USING_GLES2)
	find_package(X11)
endif()

To:

if(USING_GLES2 OR (USING_EGL AND NOT USING_FBDEV))
	find_package(X11)
endif()

Or something like that? Does that help?

-[Unknown]

[akien-mga]

Thanks, I'll try that.