[PATCH] gitk: Add ability to define an alternate temporary directory

[David Aguilar <davvid@gmail.com>]

gitk fails to show diffs when browsing a repository for which
we have read-only access.  This is due to gitk's assumption
that the current directory is always writable.

This teaches gitk to honor the GITK_TMPDIR environment
variable.  This allows users to override the default location
used for writing 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..9139ace 100755
--- a/gitk
+++ b/gitk
@@ -3170,11 +3170,15 @@ proc flist_hl {only} {
 }
 
 proc gitknewtmpdir {} {
-    global diffnum gitktmpdir gitdir
+    global diffnum env gitktmpdir gitdir
 
     if {![info exists gitktmpdir]} {
-	set gitktmpdir [file join [file dirname $gitdir] \
-			    [format ".gitk-tmp.%s" [pid]]]
+	if {[info exists env(GITK_TMPDIR)]} {
+	    set tmpdir $env(GITK_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