patch 8.2.0949: strptime() does not use DST

Problem:    Strptime() does not use DST.
Solution:   Set the tm_isdst field to -1. (Tomáš Janoušek, closes #6230)
diff --git a/src/testdir/test_functions.vim b/src/testdir/test_functions.vim
index f83264b..0a4e94e 100644
--- a/src/testdir/test_functions.vim
+++ b/src/testdir/test_functions.vim
@@ -280,6 +280,10 @@
 
   call assert_equal(1484653763, strptime('%Y-%m-%d %T', '2017-01-17 11:49:23'))
 
+  " Force DST and check that it's considered
+  let $TZ = 'WINTER0SUMMER,J1,J365'
+  call assert_equal(1484653763 - 3600, strptime('%Y-%m-%d %T', '2017-01-17 11:49:23'))
+
   call assert_fails('call strptime()', 'E119:')
   call assert_fails('call strptime("xxx")', 'E119:')
   call assert_equal(0, strptime("%Y", ''))
diff --git a/src/time.c b/src/time.c
index 272a5b5..89ff08b 100644
--- a/src/time.c
+++ b/src/time.c
@@ -314,6 +314,7 @@
     char_u	*enc;
 
     CLEAR_FIELD(tmval);
+    tmval.tm_isdst = -1;
     fmt = tv_get_string(&argvars[0]);
     str = tv_get_string(&argvars[1]);
 
diff --git a/src/version.c b/src/version.c
index 20d5081..52d655c 100644
--- a/src/version.c
+++ b/src/version.c
@@ -755,6 +755,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    949,
+/**/
     948,
 /**/
     947,