merge 8.5

2 files changed, 8 insertions, 5 deletions

diff --git a/changes b/changes
index d07ac1e..11aa8c5 100644
--- a/changes
+++ b/changes
@@ -7973,4 +7973,6 @@ improvements to regexp engine from Postgres (lane,porter,fellows,seltenreich)
 
 2015-11-20 (bug)[40f628] ListObjReplace callers fail to detect max (porter)
 
---- Released 8.5.19, December 1, 2015 --- http://core.tcl.tk/tcl/ for details
+2015-12-11 (bug)[c9eb6b] tolerate unset ::env(TZ) (gahr, nijtmans)
+
+--- Released 8.5.19, January 31, 2016 --- http://core.tcl.tk/tcl/ for details
diff --git a/generic/tclClock.c b/generic/tclClock.c
index 3ec94fb..32ba145 100644
--- a/generic/tclClock.c
+++ b/generic/tclClock.c
@@ -1994,22 +1994,23 @@ ClockSecondsObjCmd(
 static void
 TzsetIfNecessary(void)
 {
-    static char* tzWas = NULL;	/* Previous value of TZ, protected by
+    static char* tzWas = INT2PTR(-1);	/* Previous value of TZ, protected by
 				 * clockMutex. */
     const char* tzIsNow;	/* Current value of TZ */
 
     Tcl_MutexLock(&clockMutex);
     tzIsNow = getenv("TZ");
-    if (tzIsNow != NULL && (tzWas == NULL || strcmp(tzIsNow, tzWas) != 0)) {
+    if (tzIsNow != NULL && (tzWas == NULL || tzWas == INT2PTR(-1)
+	    || strcmp(tzIsNow, tzWas) != 0)) {
 	tzset();
-	if (tzWas != NULL) {
+	if (tzWas != NULL && tzWas != INT2PTR(-1)) {
 	    ckfree(tzWas);
 	}
 	tzWas = ckalloc(strlen(tzIsNow) + 1);
 	strcpy(tzWas, tzIsNow);
     } else if (tzIsNow == NULL && tzWas != NULL) {
 	tzset();
-	ckfree(tzWas);
+	if (tzWas != INT2PTR(-1)) ckfree(tzWas);
 	tzWas = NULL;
     }
     Tcl_MutexUnlock(&clockMutex);