merge(third_party/git): Merge squashed git subtree at v2.23.0

Merge commit '1b593e1ea4' as 'third_party/git'

third_party/git/blob.c

@@ -0,0 +1,20 @@
+#include "cache.h"
+#include "blob.h"
+#include "repository.h"
+#include "alloc.h"
+
+const char *blob_type = "blob";
+
+struct blob *lookup_blob(struct repository *r, const struct object_id *oid)
+{
+	struct object *obj = lookup_object(r, oid);
+	if (!obj)
+		return create_object(r, oid, alloc_blob_node(r));
+	return object_as_type(r, obj, OBJ_BLOB, 0);
+}
+
+int parse_blob_buffer(struct blob *item, void *buffer, unsigned long size)
+{
+	item->object.parsed = 1;
+	return 0;
+}