Fixed NGX_TID_T_FMT format specification for uint64_t.

Previously, "%uA" was used, which corresponds to ngx_atomic_uint_t.
Size of ngx_atomic_uint_t can be easily different from uint64_t,
leading to undefined results.

src/os/unix/ngx_thread.h

diff --git a/src/os/unix/ngx_thread.h b/src/os/unix/ngx_thread.h
index 1b52dd7..e3b5e81 100644
--- a/src/os/unix/ngx_thread.h
+++ b/src/os/unix/ngx_thread.h
@@ -47,12 +47,12 @@
 #elif (NGX_DARWIN)
 
 typedef uint64_t   ngx_tid_t;
-#define NGX_TID_T_FMT         "%uA"
+#define NGX_TID_T_FMT         "%uL"
 
 #else
 
 typedef uint64_t   ngx_tid_t;
-#define NGX_TID_T_FMT         "%uA"
+#define NGX_TID_T_FMT         "%uL"
 
 #endif