commit 749926206e72561f37e75515c698b7c73031ad11
Author: Todd Rinaldo <toddr@cpanel.net>
Date:   Fri Feb 18 13:45:15 2011 -0600

    SYS_gettid.patch
    
    Pre-AS3, SYS_gettid wasn't a supported constant. For those systems,
    block the change added to 5.1.55 by detecting the missing constant and not
    including the optional code for compile

diff --git a/mysys/stacktrace.c b/mysys/stacktrace.c
index 93e8ae6..d0723c6 100644
--- a/mysys/stacktrace.c
+++ b/mysys/stacktrace.c
@@ -51,7 +51,7 @@ void my_init_stacktrace()
 #endif
 }
 
-#ifdef __linux__
+#ifdef SYS_gettid
 
 static void print_buffer(char *buffer, size_t count)
 {
@@ -138,7 +138,7 @@ void my_safe_print_str(const char* val, int max_len)
 {
   char *heap_end;
 
-#ifdef __linux__
+#ifdef SYS_gettid
   if (!safe_print_str(val, max_len))
     return;
 #endif