Fixed build problem with Curl

Author: Semphris

mk/cmake/SuperTux/ProvideCurl.cmake

@@ -19,14 +19,10 @@ if(NOT EMSCRIPTEN)
     endif()
   endif()
 
-  if(TARGET CURL::libcurl)
-    add_library(LibCurl ALIAS CURL::libcurl)
-  else()
-    add_library(LibCurl INTERFACE IMPORTED)
-    set_target_properties(LibCurl PROPERTIES
-      INTERFACE_LINK_LIBRARIES "${CURL_LIBRARY}"
-      INTERFACE_INCLUDE_DIRECTORIES "${CURL_INCLUDE_DIRS}")
-  endif()
+  add_library(LibCurl INTERFACE IMPORTED)
+  set_target_properties(LibCurl PROPERTIES
+    INTERFACE_LINK_LIBRARIES "${CURL_LIBRARY}"
+    INTERFACE_INCLUDE_DIRECTORIES "${CURL_INCLUDE_DIRS}")
 
   set(HAVE_LIBCURL TRUE)
 endif()