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

[Iain D Sandoe <iains@gcc.gnu.org>]

https://gcc.gnu.org/g:842c7b21de346bbb55d2c973694b3c7f16f57465

commit 842c7b21de346bbb55d2c973694b3c7f16f57465
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 5fc99046d23..77b8f466566 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");
@@ -489,6 +492,7 @@ extern (C) bool runModuleUnitTests()
 
             foreach (size_t i, const(char[]) msg; bt)
                 fprintf(stderr, "%s\n", msg.ptr ? msg.ptr : "???");
+            }
         }
 
         sigaction_t action = void;
@@ -513,11 +517,15 @@ 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;