Do not build ziplib when 3MF exporter is disabled.

code/CMakeLists.txt

@@ -934,10 +934,11 @@ ELSE()
 ENDIF()
 
 # zip (https://github.com/kuba--/zip)
-IF(ASSIMP_HUNTER_ENABLED)
+IF(3MF IN_LIST ASSIMP_EXPORTERS_ENABLED)
+  IF(ASSIMP_HUNTER_ENABLED)
     hunter_add_package(zip)
     find_package(zip CONFIG REQUIRED)
-ELSE()
+  ELSE()
     SET( ziplib_SRCS
       ../contrib/zip/src/miniz.h
       ../contrib/zip/src/zip.c
@@ -952,6 +953,7 @@ ELSE()
     endif()
 
     SOURCE_GROUP( ziplib FILES ${ziplib_SRCS} )
+  ENDIF()
 ENDIF()
 
 # openddlparser
@@ -1153,9 +1155,11 @@ IF(ASSIMP_HUNTER_ENABLED)
       ZLIB::zlib
       RapidJSON::rapidjson
       utf8cpp
-      zip::zip
       pugixml
   )
+  if(TARGET zip::zip)
+    target_link_libraries(assimp PUBLIC zip::zip)
+  endif()
 
   if (ASSIMP_BUILD_DRACO)
     target_link_libraries(assimp PUBLIC ${draco_LIBRARIES})