Mark some symbols to be deprecated #minor (#698)

This change introduces the file deprecated.go, which contains any
constants, functions, and types that are slated to be deprecated in the
next major release.

These symbols are deprecated because they refer to old spellings in
pre-1.0 libgit2. This also makes the build be done with the
`-DDEPRECATE_HARD` flag to avoid regressions.

This, together with
[gorelease](https://godoc.org/golang.org/x/exp/cmd/gorelease)[1] should
make releases safer going forward.

1: More information about how that works at
   https://go.googlesource.com/exp/+/refs/heads/master/apidiff/README.md

1 files changed, 5 insertions, 5 deletions

diff --git a/git_test.go b/git_test.go
index 91ade73..1bd311a 100644
--- a/git_test.go
+++ b/git_test.go
@@ -45,16 +45,16 @@ func createBareTestRepo(t *testing.T) *Repository {
 	return repo
 }
 
-// commitOpts contains any extra options for creating commits in the seed repo
-type commitOpts struct {
+// commitOptions contains any extra options for creating commits in the seed repo
+type commitOptions struct {
 	CommitSigningCallback
 }
 
 func seedTestRepo(t *testing.T, repo *Repository) (*Oid, *Oid) {
-	return seedTestRepoOpt(t, repo, commitOpts{})
+	return seedTestRepoOpt(t, repo, commitOptions{})
 }
 
-func seedTestRepoOpt(t *testing.T, repo *Repository, opts commitOpts) (*Oid, *Oid) {
+func seedTestRepoOpt(t *testing.T, repo *Repository, opts commitOptions) (*Oid, *Oid) {
 	loc, err := time.LoadLocation("Europe/Berlin")
 	checkFatal(t, err)
 	sig := &Signature{
@@ -155,7 +155,7 @@ func TestOidZero(t *testing.T) {
 func TestEmptyOid(t *testing.T) {
 	t.Parallel()
 	_, err := NewOid("")
-	if err == nil || !IsErrorCode(err, ErrGeneric) {
+	if err == nil || !IsErrorCode(err, ErrorCodeGeneric) {
 		t.Fatal("Should have returned invalid error")
 	}
 }