Adjust to libgit2 changes

credentials.go

@@ -2,6 +2,7 @@ package git
 
 /*
 #include <git2.h>
+#include <git2/sys/cred.h>
 */
 import "C"
 import "unsafe"

go.mod

@@ -1 +1,3 @@
 module github.com/libgit2/git2go
+
+go 1.13

merge.go

@@ -132,7 +132,7 @@ func (mo *MergeOptions) toC() *C.git_merge_options {
 	}
 	return &C.git_merge_options{
 		version:          C.uint(mo.Version),
-		flags:            C.git_merge_flag_t(mo.TreeFlags),
+		flags:            C.uint32_t(mo.TreeFlags),
 		rename_threshold: C.uint(mo.RenameThreshold),
 		target_limit:     C.uint(mo.TargetLimit),
 		file_favor:       C.git_merge_file_favor_t(mo.FileFavor),
@@ -394,7 +394,7 @@ func populateCMergeFileOptions(c *C.git_merge_file_options, options MergeFileOpt
 	c.our_label = C.CString(options.OurLabel)
 	c.their_label = C.CString(options.TheirLabel)
 	c.favor = C.git_merge_file_favor_t(options.Favor)
-	c.flags = C.git_merge_file_flag_t(options.Flags)
+	c.flags = C.uint32_t(options.Flags)
 	c.marker_size = C.ushort(options.MarkerSize)
 }
 

odb.go

@@ -221,7 +221,7 @@ func (v *Odb) NewWriteStream(size int64, otype ObjectType) (*OdbWriteStream, err
 	runtime.LockOSThread()
 	defer runtime.UnlockOSThread()
 
-	ret := C.git_odb_open_wstream(&stream.ptr, v.ptr, C.git_off_t(size), C.git_object_t(otype))
+	ret := C.git_odb_open_wstream(&stream.ptr, v.ptr, C.git_object_size_t(size), C.git_object_t(otype))
 	runtime.KeepAlive(v)
 	if ret < 0 {
 		return nil, MakeGitError(ret)

stash.go

@@ -171,7 +171,7 @@ func (opts *StashApplyOptions) toC() (
 
 		optsC = &C.git_stash_apply_options{
 			version: C.GIT_STASH_APPLY_OPTIONS_VERSION,
-			flags:   C.git_stash_apply_flags(opts.Flags),
+			flags:   C.uint32_t(opts.Flags),
 		}
 		populateCheckoutOpts(&optsC.checkout_options, &opts.CheckoutOptions)
 		if opts.ProgressCallback != nil {