Fix prototypes.

--- pngphoon-1.2/tws.c	2014-09-11 22:54:21.000000000 +0100
+++ pngphoon-1.2/tws.c	2025-07-05 03:01:44.359509562 +0100
@@ -30,6 +30,7 @@
 #include <sys/types.h>
 #include <time.h>
 #include <stdlib.h>
+#include <sys/time.h>
 #ifdef  SYS5
 extern int daylight;
 extern long timezone;
@@ -37,9 +38,6 @@
 #include <sys/timeb.h>
 #endif /*SYS5*/
 
-extern long time();
-struct tm* localtime();
-
 struct tws *dtwstime()
 {
    long clock = 0;
--- pngphoon-1.2/tws.h	2014-09-21 19:58:52.000000000 +0100
+++ pngphoon-1.2/tws.h	2025-07-05 03:01:10.989993301 +0100
@@ -33,7 +33,7 @@
 
 /* Declarations of routines. */
 
-struct tws *dlocaltime( );
+struct tws *dlocaltime( long *clock );
         /* dlocaltime( &clock ) turns a time(3) clock value into a tws */
 
 struct tws *dtwstime( );