__check_max_thread_id(): add the workaround to the error message.

Change-Id: Ibaf848f90e04c2df85b0d2e82a133cd20c718bf9
diff --git a/libc/bionic/libc_init_common.cpp b/libc/bionic/libc_init_common.cpp
index 939e4e1..0665725 100644
--- a/libc/bionic/libc_init_common.cpp
+++ b/libc/bionic/libc_init_common.cpp
@@ -78,8 +78,10 @@
 #if !defined(__LP64__)
 static void __check_max_thread_id() {
   if (gettid() > 65535) {
-    async_safe_fatal("Limited by the size of pthread_mutex_t, 32 bit bionic libc only accepts "
-                     "pid <= 65535, but current pid is %d", gettid());
+    async_safe_fatal("32-bit pthread_mutex_t only supports pids <= 65535; "
+                     "current pid %d; "
+                     "`echo 65535 > /proc/sys/kernel/pid_max` as root",
+                     gettid());
   }
 }
 #endif