dir.c: rename cryptic 'which' variable to more consistent name

'el' is only *slightly* less cryptic, but is already used as the
variable name for a struct exclude_list pointer in numerous other
places, so this reduces the number of cryptic variable names in use by
one :-)

Signed-off-by: Adam Spiers <git@adamspiers.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

dir.c

@@ -349,7 +349,7 @@ void parse_exclude_pattern(const char **pattern,
 }
 
 void add_exclude(const char *string, const char *base,
-		 int baselen, struct exclude_list *which)
+		 int baselen, struct exclude_list *el)
 {
 	struct exclude *x;
 	int patternlen;
@@ -373,8 +373,8 @@ void add_exclude(const char *string, const char *base,
 	x->base = base;
 	x->baselen = baselen;
 	x->flags = flags;
-	ALLOC_GROW(which->excludes, which->nr + 1, which->alloc);
-	which->excludes[which->nr++] = x;
+	ALLOC_GROW(el->excludes, el->nr + 1, el->alloc);
+	el->excludes[el->nr++] = x;
 }
 
 static void *read_skip_worktree_file_from_index(const char *path, size_t *size)
@@ -416,7 +416,7 @@ int add_excludes_from_file_to_list(const char *fname,
 				   const char *base,
 				   int baselen,
 				   char **buf_p,
-				   struct exclude_list *which,
+				   struct exclude_list *el,
 				   int check_index)
 {
 	struct stat st;
@@ -463,7 +463,7 @@ int add_excludes_from_file_to_list(const char *fname,
 		if (buf[i] == '\n') {
 			if (entry != buf + i && entry[0] != '#') {
 				buf[i - (i && buf[i-1] == '\r')] = 0;
-				add_exclude(entry, base, baselen, which);
+				add_exclude(entry, base, baselen, el);
 			}
 			entry = buf + i + 1;
 		}

dir.h

@@ -127,11 +127,11 @@ extern int path_excluded(struct path_exclude_check *, const char *, int namelen,
 
 
 extern int add_excludes_from_file_to_list(const char *fname, const char *base, int baselen,
-					  char **buf_p, struct exclude_list *which, int check_index);
+					  char **buf_p, struct exclude_list *el, int check_index);
 extern void add_excludes_from_file(struct dir_struct *, const char *fname);
 extern void parse_exclude_pattern(const char **string, int *patternlen, int *flags, int *nowildcardlen);
 extern void add_exclude(const char *string, const char *base,
-			int baselen, struct exclude_list *which);
+			int baselen, struct exclude_list *el);
 extern void free_excludes(struct exclude_list *el);
 extern int file_exists(const char *);