Linux specific modifications:
	- #include stdint.h for uint32_t
	- #define timespeccmp() which is sys/time.h in OpenBSD
	- Linux doesn't have any LOCK flags for open(2), so use flock(2) instead

--- ../ksh-openbsd49/history.c	2011-09-01 08:09:51.486181269 +0200
+++ history.c	2011-09-01 08:08:59.657181265 +0200
@@ -17,11 +17,17 @@
 #include "sh.h"
 #include <sys/stat.h>
 #include "strlcat.h"
+#include "stdint.h"
 
 #ifdef HISTORY
 # include <sys/file.h>
 # include <sys/mman.h>
 
+#define timespeccmp(tsp, usp, cmp)			\
+	(((tsp)->tv_sec == (usp)->tv_sec) ?		\
+	    ((tsp)->tv_nsec cmp (usp)->tv_nsec) :	\
+	    ((tsp)->tv_sec cmp (usp)->tv_sec))
+
 static void	writehistfile(FILE *);
 static FILE    *history_open(int *);
 static int	history_load(FILE *, Source *);
@@ -604,7 +610,9 @@
 	FILE		*f = NULL;
 	struct stat	sb;
 
-	if ((fd = open(hname, O_RDWR | O_CREAT | O_EXLOCK, 0600)) == -1)
+	if ((fd = open(hname, O_RDWR | O_CREAT, 0600)) == -1)
+		return (NULL);
+	if (flock(fd, LOCK_EX) == -1)
 		return (NULL);
 	f = fdopen(fd, "r+");
 	if (f == NULL) {