libsass: use dependency() instead of declare_dependency()

for the dummy dependency case

Author: lazka

subprojects/packagefiles/libsass/src/meson.build

@@ -83,7 +83,7 @@ if host_machine.system() != 'windows'
     dl_dep = cc.find_library('dl', required : false)
   endif
 else
-  dl_dep = declare_dependency()
+  dl_dep = dependency('', required: false)
 endif
 
 lib_args = []