Add a new option 'core.askpass'.

Setting this option has the same effect as setting the environment variable
'GIT_ASKPASS'.

Signed-off-by: Knut Franke <k.franke@science-computing.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/config.txt

@@ -450,6 +450,12 @@ core.excludesfile::
 	to the value of `$HOME` and "{tilde}user/" to the specified user's
 	home directory.  See linkgit:gitignore[5].
 
+core.askpass::
+	Some commands (e.g. svn and http interfaces) that interactively
+	ask for a password can be told to use an external program given
+	via the value of this variable when it is set, and the
+	environment variable `GIT_ASKPASS` is not set.
+
 core.editor::
 	Commands such as `commit` and `tag` that lets you edit
 	messages by launching an editor uses the value of this

cache.h

@@ -1029,6 +1029,7 @@ extern int pager_in_use(void);
 extern int pager_use_color;
 
 extern const char *editor_program;
+extern const char *askpass_program;
 extern const char *excludes_file;
 
 /* base85 */

config.c

@@ -560,6 +560,9 @@ static int git_default_core_config(const char *var, const char *value)
 	if (!strcmp(var, "core.editor"))
 		return git_config_string(&editor_program, var, value);
 
+	if (!strcmp(var, "core.askpass"))
+		return git_config_string(&askpass_program, var, value);
+
 	if (!strcmp(var, "core.excludesfile"))
 		return git_config_pathname(&excludes_file, var, value);
 

connect.c

@@ -621,12 +621,14 @@ int finish_connect(struct child_process *conn)
 
 char *git_getpass(const char *prompt)
 {
-	char *askpass;
+	const char *askpass;
 	struct child_process pass;
 	const char *args[3];
 	static struct strbuf buffer = STRBUF_INIT;
 
 	askpass = getenv("GIT_ASKPASS");
+	if (!askpass)
+		askpass = askpass_program;
 
 	if (!askpass || !(*askpass))
 		return getpass(prompt);

environment.c

@@ -37,6 +37,7 @@ size_t delta_base_cache_limit = 16 * 1024 * 1024;
 const char *pager_program;
 int pager_use_color = 1;
 const char *editor_program;
+const char *askpass_program;
 const char *excludes_file;
 enum auto_crlf auto_crlf = AUTO_CRLF_FALSE;
 int read_replace_refs = 1;