Link to xcb as system-provided targets, instead of by direct library path (#4221)

Signed-off-by: Chris Burel <burelc@amazon.com>

Code/Framework/AzFramework/Platform/Linux/platform_linux.cmake

@@ -10,17 +10,12 @@
 # Only 'xcb' and 'wayland' are recognized
 if (${PAL_TRAIT_LINUX_WINDOW_MANAGER} STREQUAL "xcb")
 
-    find_library(XCB_LIBRARY xcb)
-    find_library(XCB_XKB_LIBRARY xcb-xkb)
-    find_library(XKBCOMMON_LIBRARY xkbcommon)
-    find_library(XKBCOMMON_X11_LIBRARY xkbcommon-x11)
-
     set(LY_BUILD_DEPENDENCIES
         PRIVATE
-            ${XCB_LIBRARY}
-            ${XKBCOMMON_LIBRARY}
-            ${XKBCOMMON_X11_LIBRARY}
-            ${XCB_XKB_LIBRARY}
+            3rdParty::X11::xcb
+            3rdParty::X11::xcb_xkb
+            3rdParty::X11::xkbcommon
+            3rdParty::X11::xkbcommon_X11
     )
 
     set(LY_COMPILE_DEFINITIONS PUBLIC PAL_TRAIT_LINUX_WINDOW_MANAGER_XCB)

cmake/3rdParty/FindX11.cmake

@@ -0,0 +1,29 @@
+#
+# Copyright (c) Contributors to the Open 3D Engine Project.
+# For complete copyright and license terms please see the LICENSE at the root of this distribution.
+#
+# SPDX-License-Identifier: Apache-2.0 OR MIT
+#
+#
+
+# Open a new scope so we can make changes to CMAKE_MODULE_PATH, and restore it
+# when we're done
+function(FindX11)
+    # O3DE's FindX11.cmake is a wrapper for the one that CMake provides. Remove
+    # our current directory from CMAKE_MODULE_PATH to avoid recursive includes
+    list(REMOVE_ITEM CMAKE_MODULE_PATH ${CMAKE_CURRENT_LIST_DIR})
+
+    find_package(X11 COMPONENTS ${X11_FIND_COMPONENTS} QUIET)
+
+    foreach(component IN LISTS X11_FIND_COMPONENTS)
+        ly_add_external_target(
+            SYSTEM
+            PACKAGE X11
+            NAME ${component}
+            VERSION ""
+            BUILD_DEPENDENCIES
+                X11::${component}
+        )
+    endforeach()
+endfunction()
+FindX11()

cmake/LYWrappers.cmake

@@ -477,11 +477,23 @@ function(ly_parse_third_party_dependencies ly_THIRD_PARTY_LIBRARIES)
         if(${dependency_namespace} STREQUAL "3rdParty")
             if (NOT TARGET ${dependency})
                 list(GET dependency_list 1 dependency_package)
+                list(LENGTH dependency_list dependency_list_length)
                 ly_download_associated_package(${dependency_package})
-                find_package(${dependency_package} REQUIRED MODULE)
+                if (dependency_list_length GREATER 2)
+                    # There's an optional interface specified
+                    list(GET dependency_list 2 component)
+                    list(APPEND packages_with_components ${dependency_package})
+                    list(APPEND ${dependency_package}_components ${component})
+                else()
+                    find_package(${dependency_package} REQUIRED MODULE)
+                endif()
             endif()
         endif()
     endforeach()
+
+    foreach(dependency IN LISTS packages_with_components)
+        find_package(${dependency} REQUIRED MODULE COMPONENTS ${${dependency}_components})
+    endforeach()
 endfunction()
 
 #! ly_configure_target_platform_properties: Configures any platform specific properties on target