[gimp] Bug 795510 - SYS_gettid is not available on non-Linux system.

[Jehan Pagès <jehanp src gnome org>]

commit 106fc9309f2884bb91f2c9c6a17a9aa3e67c359b
Author: Jehan <jehan girinstud io>
Date:   Wed Apr 25 00:19:37 2018 +0200

    Bug 795510 - SYS_gettid is not available on non-Linux system.
    
    I could not find for sure what to use on FreeBSD instead, so let's just
    not get this information there. It is quite useful information to know
    where thread traces were asked from, but it is more important to make
    sure the program can be compiled everywhere. Also we can just check
    which thread has gimp_stack_trace*() calls. Thus it can be seen as
    redundant information in any case.
    
    SYS_gettid is apparently defined as a macro, so let's simply check for
    it being defined.

 libgimpbase/gimputils.c |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)
---
diff --git a/libgimpbase/gimputils.c b/libgimpbase/gimputils.c
index eb2c5ad..d95528f 100644
--- a/libgimpbase/gimputils.c
+++ b/libgimpbase/gimputils.c
@@ -1178,7 +1178,7 @@ gimp_stack_trace_print (const gchar   *prog_name,
   pid_t    pid = getpid();
 #if defined(G_OS_WIN32)
   DWORD    tid = GetCurrentThreadId ();
-#else
+#elif defined(SYS_gettid)
   long     tid = syscall (SYS_gettid);
 #endif
 
@@ -1272,16 +1272,20 @@ gimp_stack_trace_print (const gchar   *prog_name,
         {
           if (! stack_printed)
             {
+#if defined(G_OS_WIN32) || defined(SYS_gettid)
               if (stream)
                 g_fprintf (stream,
                            "\n# Stack traces obtained from PID %d - Thread %lu #\n\n",
                            pid, tid);
+#endif
               if (trace)
                 {
                   gtrace = g_string_new (NULL);
+#if defined(G_OS_WIN32) || defined(SYS_gettid)
                   g_string_printf (gtrace,
                                    "\n# Stack traces obtained from PID %d - Thread %lu #\n\n",
                                    pid, tid);
+#endif
                 }
             }
           /* It's hard to know if the debugger was found since it