zsh/system: Fix infinite loop in sysread

ChangeLog

@@ -1,5 +1,8 @@
 2020-02-06  dana  <dana@dana.is>
 
+	* Roman Perepelitsa: 45382: Src/Modules/system.c: Fix infinite
+	loop in sysread
+
 	* Martin von Wittich: 45388 (tweaked):
 	Completion/Unix/Type/_diff_options: Restore -w completion lost
 	in workers/43351

Src/Modules/system.c

@@ -174,7 +174,7 @@ bin_sysread(char *nam, char **args, Options ops, UNUSED(int func))
 	}
 
 	while ((ret = select(infd+1, (SELECT_ARG_2_T) &fds,
-			     NULL, NULL,&select_tv)) < 1) {
+			     NULL, NULL,&select_tv)) < 0) {
 	    if (errno != EINTR || errflag || retflag || breaks || contflag)
 		break;
 	}