bump vendored libpng from 1.6.40 to 1.6.41 and zlib from 1.3 to 1.3.1.

Author: sezero

.gitmodules

@@ -9,7 +9,7 @@
 [submodule "external/libpng"]
 	path = external/libpng
 	url = https://github.com/libsdl-org/libpng.git
-	branch = v1.6.40-SDL
+	branch = v1.6.41-SDL
 [submodule "external/libwebp"]
 	path = external/libwebp
 	url = https://github.com/libsdl-org/libwebp.git
@@ -21,7 +21,7 @@
 [submodule "external/zlib"]
 	path = external/zlib
 	url = https://github.com/libsdl-org/zlib.git
-	branch = v1.3-SDL
+	branch = v1.3.1-SDL
 [submodule "external/libjxl"]
 	path = external/libjxl
 	url = https://github.com/libsdl-org/libjxl.git

CMakeLists.txt

@@ -399,6 +399,8 @@ if(SDL3IMAGE_ZLIB)
         message(STATUS "${PROJECT_NAME}: Using vendored zlib")
         sdl_check_project_in_subfolder(external/zlib zlib SDL3IMAGE_VENDORED)
         add_subdirectory(external/zlib EXCLUDE_FROM_ALL)
+        # disable build of zlib example programs:
+        set(ZLIB_BUILD_EXAMPLES OFF CACHE BOOL "zlib examples" FORCE)
         # PNG_BUILD_ZLIB variable is used by vendored libpng
         set(PNG_BUILD_ZLIB ON CACHE BOOL "libpng option to tell it should use 'our' vendored ZLIB library" FORCE)
         # ZLIB_INCLUDE_DIR variable is used by vendored libpng