Move commit GPG signature verification to commit.c

Signed-off-by: Sebastian Götte <jaseg@physik-pool.tu-berlin.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

gpg-interface.h

@@ -1,6 +1,17 @@
 #ifndef GPG_INTERFACE_H
 #define GPG_INTERFACE_H
 
+struct signature_check {
+	char *gpg_output;
+	char *gpg_status;
+	char result; /* 0 (not checked),
+		      * N (checked but no further result),
+		      * G (good)
+		      * B (bad) */
+	char *signer;
+	char *key;
+};
+
 extern int sign_buffer(struct strbuf *buffer, struct strbuf *signature, const char *signing_key);
 extern int verify_signed_buffer(const char *payload, size_t payload_size, const char *signature, size_t signature_size, struct strbuf *gpg_output, struct strbuf *gpg_status);
 extern int git_gpg_config(const char *, const char *, void *);