[gcc(refs/users/ibuclaw/heads/darwin)] Darwin D : Disable backtraces for Darwin for now.

[Iain Buclaw]

https://gcc.gnu.org/g:323519f00ece477489aca9845496c426de553f13

commit 323519f00ece477489aca9845496c426de553f13
Author: Iain Sandoe <iain@sandoe.co.uk>
Date:   Sat Dec 19 13:21:46 2020 +0000

    Darwin D : Disable backtraces for Darwin for now.
    
    It seems that there is some fault in the handling of these that
    causes the process to spin if the backtrace is attempted in most
    cases.

Diff:
---
 libphobos/libdruntime/core/runtime.d | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/libphobos/libdruntime/core/runtime.d b/libphobos/libdruntime/core/runtime.d
index 848b607ae69..508cc0fc563 100644
--- a/libphobos/libdruntime/core/runtime.d
+++ b/libphobos/libdruntime/core/runtime.d
@@ -479,6 +479,9 @@ extern (C) bool runModuleUnitTests()
 
         static extern (C) void unittestSegvHandler( int signum, siginfo_t* info, void* ptr )
         {
+            version(Darwin) {}
+            else
+            {
             import core.stdc.stdio;
             fprintf(stderr, "Segmentation fault while running unittests:\n");
             fprintf(stderr, "----------------\n");
@@ -497,6 +500,7 @@ extern (C) bool runModuleUnitTests()
 
             foreach (size_t i, const(char[]) msg; bt)
                 fprintf(stderr, "%s\n", msg.ptr ? msg.ptr : "???");
+            }
         }
 
         sigaction_t action = void;
@@ -521,11 +525,15 @@ extern (C) bool runModuleUnitTests()
 
         static extern (C) void unittestSegvHandler( int signum, siginfo_t* info, void* ptr ) nothrow
         {
+            version(Darwin) {}
+            else
+            {
             static enum MAXFRAMES = 128;
             void*[MAXFRAMES]  callstack;
 
             auto numframes = backtrace( callstack.ptr, MAXFRAMES );
             backtrace_symbols_fd( callstack.ptr, numframes, 2 );
+            }
         }
 
         sigaction_t action = void;