git-format-patch: add a new format.cc configuration variable

Some projects prefer to always CC patches to a given mailing list. In
these cases, it's handy to configure that address once.
Signed-off-by: NMiklos Vajna <vmiklos@frugalware.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Documentation/git-format-patch.txt

@@ -168,6 +168,7 @@ and file suffix, and number patches when outputting more than one.
         subjectprefix = CHANGE
         suffix = .txt
         numbered = auto
+	cc = <email>
 ------------
 
 

builtin-log.c

@@ -485,6 +485,13 @@ static int git_format_config(const char *var, const char *value)
 		fmt_patch_suffix = xstrdup(value);
 		return 0;
 	}
+	if (!strcmp(var, "format.cc")) {
+		if (!value)
+			return config_error_nonbool(var);
+		ALLOC_GROW(extra_cc, extra_cc_nr + 1, extra_cc_alloc);
+		extra_cc[extra_cc_nr++] = xstrdup(value);
+		return 0;
+	}
 	if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
 		return 0;
 	}