[PATCH] getenv/setenv: use constants if available

[Matthias Lederhofer <matled@gmx.net>]

There were places using "GIT_DIR" instead of GIT_DIR_ENVIRONMENT and
"GIT_CONFIG" instead of CONFIG_ENVIRONMENT.  This makes it easier to
find all places touching an environment variable using git grep or
similar tools.

Signed-off-by: Matthias Lederhofer <matled@gmx.net>
---
I only found one other place where a string was used directly even
though there is a constant: GIT_REFLOG_ACTION is only defined in
git-revert.c and builtin-fetch--tool.c uses the environment variable
too.  At least when searching with grep this makes no problem because
the name of the constant is the same as the string it is defined to..
---
 builtin-config.c |    4 ++--
 path.c           |    2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/builtin-config.c b/builtin-config.c
index 3f7cab1..7d2063c 100644
--- a/builtin-config.c
+++ b/builtin-config.c
@@ -178,14 +178,14 @@ int cmd_config(int argc, const char **argv, const char *prefix)
 			char *home = getenv("HOME");
 			if (home) {
 				char *user_config = xstrdup(mkpath("%s/.gitconfig", home));
-				setenv("GIT_CONFIG", user_config, 1);
+				setenv(CONFIG_ENVIRONMENT, user_config, 1);
 				free(user_config);
 			} else {
 				die("$HOME not set");
 			}
 		}
 		else if (!strcmp(argv[1], "--system"))
-			setenv("GIT_CONFIG", ETC_GITCONFIG, 1);
+			setenv(CONFIG_ENVIRONMENT, ETC_GITCONFIG, 1);
 		else if (!strcmp(argv[1], "--null") || !strcmp(argv[1], "-z")) {
 			term = '\0';
 			delim = '\n';
diff --git a/path.c b/path.c
index 6395cf2..c4ce962 100644
--- a/path.c
+++ b/path.c
@@ -252,7 +252,7 @@ char *enter_repo(char *path, int strict)
 
 	if (access("objects", X_OK) == 0 && access("refs", X_OK) == 0 &&
 	    validate_headref("HEAD") == 0) {
-		setenv("GIT_DIR", ".", 1);
+		setenv(GIT_DIR_ENVIRONMENT, ".", 1);
 		check_repository_format();
 		return path;
 	}
-- 
1.5.2.2.1398.ga4b05