build(wayland): ensure libdrm is found (#4070)

cmake/compile_definitions/linux.cmake

@@ -85,18 +85,27 @@ if(CUDA_FOUND)
     add_compile_definitions(SUNSHINE_BUILD_CUDA)
 endif()
 
-# drm
-if(${SUNSHINE_ENABLE_DRM})
+# libdrm is required for both DRM (KMS) and Wayland
+if(${SUNSHINE_ENABLE_DRM} OR ${SUNSHINE_ENABLE_WAYLAND})
     find_package(LIBDRM REQUIRED)
-    find_package(LIBCAP REQUIRED)
 else()
     set(LIBDRM_FOUND OFF)
+endif()
+if(LIBDRM_FOUND)
+    include_directories(SYSTEM ${LIBDRM_INCLUDE_DIRS})
+    list(APPEND PLATFORM_LIBRARIES ${LIBDRM_LIBRARIES})
+endif()
+
+# drm
+if(${SUNSHINE_ENABLE_DRM})
+    find_package(LIBCAP REQUIRED)
+else()
     set(LIBCAP_FOUND OFF)
 endif()
 if(LIBDRM_FOUND AND LIBCAP_FOUND)
     add_compile_definitions(SUNSHINE_BUILD_DRM)
-    include_directories(SYSTEM ${LIBDRM_INCLUDE_DIRS} ${LIBCAP_INCLUDE_DIRS})
-    list(APPEND PLATFORM_LIBRARIES ${LIBDRM_LIBRARIES} ${LIBCAP_LIBRARIES})
+    include_directories(SYSTEM ${LIBCAP_INCLUDE_DIRS})
+    list(APPEND PLATFORM_LIBRARIES ${LIBCAP_LIBRARIES})
     list(APPEND PLATFORM_TARGET_FILES
             "${CMAKE_SOURCE_DIR}/src/platform/linux/kmsgrab.cpp")
     list(APPEND SUNSHINE_DEFINITIONS EGL_NO_X11=1)