bundle-uri: create "key=value" line parsing

When advertising a bundle list over Git's protocol v2, we will use
packet lines. Each line will be of the form "key=value" representing a
bundle list. Connect the API necessary for Git's transport to the
key-value pair parsing created in the previous change.

We are not currently implementing this protocol v2 functionality, but
instead preparing to expose this parsing to be unit-testable.

Co-authored-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

bundle-uri.h

@@ -67,4 +67,16 @@ int for_all_bundles_in_list(struct bundle_list *list,
  */
 int fetch_bundle_uri(struct repository *r, const char *uri);
 
+/**
+ * General API for {transport,connect}.c etc.
+ */
+
+/**
+ * Parse a "key=value" packet line from the bundle-uri verb.
+ *
+ * Returns 0 on success and non-zero on error.
+ */
+int bundle_uri_parse_line(struct bundle_list *list,
+			  const char *line);
+
 #endif