more libgit2 version diff handled

go.mod

@@ -1,4 +1,5 @@
-module github.com/libgit2/git2go/v34
+//module github.com/libgit2/git2go/v34
+module git2go
 
 go 1.13
 

remote.go

@@ -6,6 +6,10 @@ package git
 #include <git2.h>
 #include <git2/sys/cred.h>
 
+static void set_update_fetchhead(git_fetch_options *opts, int v) {
+	opts->update_fetchhead = v;
+}
+
 extern void _go_git_populate_remote_callbacks(git_remote_callbacks *callbacks);
 */
 import "C"
@@ -983,7 +987,10 @@ func populateFetchOptions(copts *C.git_fetch_options, opts *FetchOptions, errorT
 	}
 	populateRemoteCallbacks(&copts.callbacks, &opts.RemoteCallbacks, errorTarget)
 	copts.prune = C.git_fetch_prune_t(opts.Prune)
-	copts.update_fetchhead = ucbool(opts.UpdateFetchhead)
+
+	// use the helper. the update_fetchhead is signed on libgit2 1.5 but unsigined on 1.9
+	//copts.update_fetchhead = ucbool(opts.UpdateFetchhead)
+	C.set_update_fetchhead(copts, C.int(ucbool(opts.UpdateFetchhead)))
 	copts.download_tags = C.git_remote_autotag_option_t(opts.DownloadTags)
 
 	copts.custom_headers = C.git_strarray{

wrapper.c

@@ -4,7 +4,9 @@
 #include <git2/sys/odb_backend.h>
 #include <git2/sys/refdb_backend.h>
 #include <git2/sys/cred.h>
+#if (LIBGIT2_VER_MAJOR > 1) || (LIBGIT2_VER_MAJOR == 1 && LIBGIT2_VER_MINOR >= 9)
 #include <git2/sys/errors.h>
+#endif
 
 // There are two ways in which to declare a callback:
 //