Improved compatibility with other Unix systems.

include/sys/types.h

@@ -43,6 +43,9 @@ typedef long clock_t;		   /* unit for system accounting */
 typedef unsigned long sigset_t;
 #endif
 
+/* Open Group Base Specifications Issue 6 (not complete) */
+typedef long useconds_t;	/* Time in microseconds */
+
 /* Types used in disk, inode, etc. data structures. */
 typedef short          dev_t;	   /* holds (major|minor) device pair */
 typedef char           gid_t;	   /* group id */
@@ -116,4 +119,10 @@ typedef int           Mode_t;
 /* Signal handler type, e.g. SIG_IGN */
 typedef void _PROTOTYPE( (*sighandler_t), (int) );
 
+/* Compatibility with other systems */
+typedef unsigned char	u_char;
+typedef unsigned short	u_short;
+typedef unsigned int	u_int;
+typedef unsigned long	u_long;
+
 #endif /* _TYPES_H */