w32_stack: treat a len as an size_t

src/win32/w32_stack.c

@@ -91,10 +91,10 @@ int git_win32__stack_format(
 	} s;
 
 	IMAGEHLP_LINE64 line;
-	int buf_used = 0;
+	size_t buf_used = 0;
 	unsigned int k;
 	char detail[MY_MAX_FILENAME * 2]; /* filename plus space for function name and formatting */
-	int detail_len;
+	size_t detail_len;
 
 	if (!g_win32_stack_initialized) {
 		git_error_set(GIT_ERROR_INVALID, "git_win32_stack not initialized.");

src/win32/w32_stack.h

@@ -38,7 +38,7 @@ typedef void (*git_win32__stack__aux_cb_alloc)(unsigned int *aux_id);
  * @param aux_msg A buffer where a formatted message should be written.
  * @param aux_msg_len The size of the buffer.
  */
-typedef void (*git_win32__stack__aux_cb_lookup)(unsigned int aux_id, char *aux_msg, unsigned int aux_msg_len);
+typedef void (*git_win32__stack__aux_cb_lookup)(unsigned int aux_id, char *aux_msg, size_t aux_msg_len);
 
 /**
  * Register an "aux" data provider to augment our C stacktrace data.