fix comment

lib/config.dos

@@ -64,7 +64,7 @@
 #define STDC_HEADERS           1
 #define TIME_WITH_SYS_TIME     1
 
-/* Qualifiers for send(), recv() and recv(). */
+/* Qualifiers for send(), recv() and recvfrom(). */
 
 #define SEND_TYPE_ARG1         int
 #define SEND_QUAL_ARG2         const