patch 8.0.1182: cannot see or change mzscheme dll name

Problem:    Cannot see or change mzscheme dll name.
Solution:   Add 'mzschemedll' and 'mzschemegcdll'.
diff --git a/src/if_mzsch.c b/src/if_mzsch.c
index c9c5969..54474bd 100644
--- a/src/if_mzsch.c
+++ b/src/if_mzsch.c
@@ -757,7 +757,7 @@
 mzscheme_enabled(int verbose)
 {
     return mzscheme_runtime_link_init(
-	    DYNAMIC_MZSCH_DLL, DYNAMIC_MZGC_DLL, verbose) == OK;
+	    (char *)p_mzschemedll, (char *)p_mzschemegcdll, verbose) == OK;
 }
 
     static void