Update assimp to fix Mac CI.

Zlib no longer uses fdopen.
Zlib previously had redefined fdopen, causing conflicts in apple things.
Zlib has since updated to remove these defines, fixing the issue.

CMakeLists.txt

@@ -157,8 +157,15 @@ list(APPEND VAR_NAMES QT6_INSTALL_PLUGINS)
 
 # Find Assimp.
 if(QTK_SUBMODULES)
+  if(APPLE)
+    # Avoid zlib redefining fdopen, causing build failures in apple clang.
+    # https://github.com/assimp/assimp/issues/6118
+    add_compile_definitions(-Dfdopen=fdopen)
+  endif()
+  if(NOT WIN32)
+    add_compile_options(-fPIC)
+  endif()
   # Required to statically link.
-  add_compile_options(-fPIC)
   set(BUILD_SHARED_LIBS OFF CACHE STRING "Build static assimp libs" FORCE)
   set(ASSIMP_BUILD_ZLIB ON CACHE STRING "Build Zlib with assimp." FORCE)
   set(
@@ -175,6 +182,14 @@ if(QTK_SUBMODULES)
       "${CMAKE_CURRENT_SOURCE_DIR}/extern/assimp/assimp/"
       EXCLUDE_FROM_ALL
   )
+  install(
+      TARGETS assimp zlibstatic
+      EXPORT qtk_export
+      COMPONENT qtk
+      ARCHIVE DESTINATION lib
+      LIBRARY DESTINATION lib
+      RUNTIME DESTINATION bin
+  )
 else()
   find_package(assimp REQUIRED)
 endif()