force SDL build on linux to include libdecor for wayland

.github/workflows/c-cpp.yml

@@ -44,6 +44,7 @@ jobs:
         run: |
           sudo apt-get update
           sudo apt-get -y install ccache libao-dev libasound2-dev libevdev-dev libgl1-mesa-dev liblua5.3-dev libminiupnpc-dev libpulse-dev libsdl2-dev libudev-dev libzip-dev ninja-build libcurl4-openssl-dev
+          sudo apt-get -y install libwayland-dev libdecor-0-dev libaudio-dev libjack-dev libsndio-dev libsamplerate0-dev libx11-dev libxext-dev libxrandr-dev libxcursor-dev libxfixes-dev libxi-dev libxss-dev libxkbcommon-dev libdrm-dev libgbm-dev libgles2-mesa-dev libegl1-mesa-dev libdbus-1-dev libibus-1.0-dev libudev-dev fcitx-libs-dev
         if: runner.os == 'Linux'
 
       - name: Set up build environment (Windows, MinGW)

CMakeLists.txt

@@ -356,7 +356,7 @@ if(NOT LIBRETRO)
 	endif()
 
 	if(NOT ANDROID AND NOT IOS)
-		if(NOT APPLE)
+		if(NOT APPLE AND NOT LINUX)
 			find_package(SDL2)
 		endif()
 		if(NOT SDL2_FOUND)