[PATCH] gitk: Honor TMPDIR when viewing diffs externally

[David Aguilar <davvid@gmail.com>]

gitk's external diff fails when browsing read-only repositories.
This is due to gitk's assumption that the current directory is
always writable.  By honoring TMPDIR we avoid this problem and
allow users to define the location used for temporary files.

Signed-off-by: David Aguilar <davvid@gmail.com>
---
 gitk |   10 +++++++---
 1 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/gitk b/gitk
index db5ec54..a065e94 100755
--- a/gitk
+++ b/gitk
@@ -3170,11 +3170,15 @@ proc flist_hl {only} {
 }
 
 proc gitknewtmpdir {} {
-    global diffnum gitktmpdir gitdir
+    global diffnum gitktmpdir gitdir env
 
     if {![info exists gitktmpdir]} {
-	set gitktmpdir [file join [file dirname $gitdir] \
-			    [format ".gitk-tmp.%s" [pid]]]
+	if {[info exists env(TMPDIR)]} {
+	    set tmpdir $env(TMPDIR)
+	} else {
+	    set tmpdir [file dirname $gitdir]
+	}
+	set gitktmpdir [file join $tmpdir [format ".gitk-tmp.%s" [pid]]]
 	if {[catch {file mkdir $gitktmpdir} err]} {
 	    error_popup "[mc "Error creating temporary directory %s:" $gitktmpdir] $err"
 	    unset gitktmpdir
-- 
1.6.5.2.180.gc5b3e