Blame: change signature to be more binding-friendly

include/git2/blame.h

@@ -183,7 +183,7 @@ GIT_EXTERN(int) git_blame_buffer(
 		git_blame **out,
 		git_blame *reference,
 		const char *buffer,
-		size_t buffer_len);
+		uint32_t buffer_len);
 
 /**
  * Free memory allocated by git_blame_file or git_blame_buffer.

src/blame.c

@@ -448,7 +448,7 @@ int git_blame_buffer(
 		git_blame **out,
 		git_blame *reference,
 		const char *buffer,
-		size_t buffer_len)
+		uint32_t buffer_len)
 {
 	git_blame *blame;
 	git_diff_options diffopts = GIT_DIFF_OPTIONS_INIT;