Improve GetNextToken() performance
diff --git a/MagickCore/opencl.c b/MagickCore/opencl.c
index dd1b29a..7826722 100644
--- a/MagickCore/opencl.c
+++ b/MagickCore/opencl.c
@@ -766,7 +766,7 @@
     /*
       Interpret XML.
     */
-    GetNextToken(q,&q,extent,token);
+    (void) GetNextToken(q,&q,extent,token);
     if (*token == '\0')
       break;
     (void) CopyMagickString(keyword,token,MagickPathExtent);
@@ -776,7 +776,7 @@
           Doctype element.
         */
         while ((LocaleNCompare(q,"]>",2) != 0) && (*q != '\0'))
-          GetNextToken(q,&q,extent,token);
+          (void) GetNextToken(q,&q,extent,token);
         continue;
       }
     if (LocaleNCompare(keyword,"<!--",4) == 0)
@@ -785,7 +785,7 @@
           Comment element.
         */
         while ((LocaleNCompare(q,"->",2) != 0) && (*q != '\0'))
-          GetNextToken(q,&q,extent,token);
+          (void) GetNextToken(q,&q,extent,token);
         continue;
       }
     if (LocaleCompare(keyword,"<device") == 0)
@@ -837,11 +837,11 @@
           device_benchmark);
         continue;
       }
-    GetNextToken(q,(const char **) NULL,extent,token);
+    (void) GetNextToken(q,(const char **) NULL,extent,token);
     if (*token != '=')
       continue;
-    GetNextToken(q,&q,extent,token);
-    GetNextToken(q,&q,extent,token);
+    (void) GetNextToken(q,&q,extent,token);
+    (void) GetNextToken(q,&q,extent,token);
     switch (*keyword)
     {
       case 'M':