* process.c (wait_reading_process_input): If we're running

	Solaris, it's not necessary to check if we should redeliver SIGIO,
	according to David Mackenzie.
	* s/sol2.h: #include "usg5-4.h", and #define const.

src/process.c

@@ -1841,7 +1841,7 @@ wait_reading_process_input (time_limit, microsecs, read_kbd, do_display)
 	  else
 	    error("select error: %s", sys_errlist[xerrno]);
 	}
-#ifdef sun
+#if defined(sun) && !defined(USG5_4)
       else if (nfds > 0 && FD_ISSET (0, &Available) && interrupt_input)
 	/* System sometimes fails to deliver SIGIO.  */
 	kill (getpid (), SIGIO);

src/s/sol2.h

-#include "s-usg5-4.h"
+#include "usg5-4.h"
 
 #define POSIX
 
@@ -17,6 +17,7 @@
 #else /* GCC */
 #define C_SWITCH_SYSTEM -traditional
 #endif /* GCC */
+#define const
 
 /* Karl Berry writes:
 If you have the misfortune to be running Solaris 2.1, you may have