[gcc(refs/users/ibuclaw/heads/darwin)] libphobos: Fix broken ucontext implementation, and other small test fixes

[Iain Buclaw <ibuclaw@gcc.gnu.org>]

https://gcc.gnu.org/g:5646288fb9f20cbcb6ca3aa704bc686d6a24759f

commit 5646288fb9f20cbcb6ca3aa704bc686d6a24759f
Author: Iain Buclaw <ibuclaw@gdcproject.org>
Date:   Wed Dec 9 10:49:34 2020 +0100

    libphobos: Fix broken ucontext implementation, and other small test fixes

Diff:
---
 libphobos/libdruntime/core/thread/fiber.d               | 1 +
 libphobos/libdruntime/core/thread/threadbase.d          | 1 +
 libphobos/src/std/experimental/allocator/package.d      | 3 ++-
 libphobos/testsuite/libphobos.thread/fiber_guard_page.d | 6 ++++--
 4 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/libphobos/libdruntime/core/thread/fiber.d b/libphobos/libdruntime/core/thread/fiber.d
index 3270f2e7094..2b475ca82cb 100644
--- a/libphobos/libdruntime/core/thread/fiber.d
+++ b/libphobos/libdruntime/core/thread/fiber.d
@@ -883,6 +883,7 @@ class Fiber
      */
     static Fiber getThis() @safe nothrow @nogc
     {
+        version (GNU) pragma(inline, false);
         return sm_this;
     }
 
diff --git a/libphobos/libdruntime/core/thread/threadbase.d b/libphobos/libdruntime/core/thread/threadbase.d
index c2c2333efe9..50795e444be 100644
--- a/libphobos/libdruntime/core/thread/threadbase.d
+++ b/libphobos/libdruntime/core/thread/threadbase.d
@@ -313,6 +313,7 @@ class ThreadBase
         // NOTE: This function may not be called until thread_init has
         //       completed.  See thread_suspendAll for more information
         //       on why this might occur.
+        version (GNU) pragma(inline, false);
         return sm_this;
     }
 
diff --git a/libphobos/src/std/experimental/allocator/package.d b/libphobos/src/std/experimental/allocator/package.d
index 11c85474365..7c404070ffa 100644
--- a/libphobos/src/std/experimental/allocator/package.d
+++ b/libphobos/src/std/experimental/allocator/package.d
@@ -622,7 +622,8 @@ allocator can be cast to $(D shared).
 
     testAllocatorObject(processAllocator);
     testAllocatorObject(theAllocator);
-    assertThrown!AssertError(processAllocator = null);
+    // XBUG: Asserts are not thrown in release code, so is a pointless check.
+    //assertThrown!AssertError(processAllocator = null);
 
     // Restore initial processAllocator state
     processAllocator = oldProcessAllocator;
diff --git a/libphobos/testsuite/libphobos.thread/fiber_guard_page.d b/libphobos/testsuite/libphobos.thread/fiber_guard_page.d
index 9f754e155d2..ca54a19857f 100644
--- a/libphobos/testsuite/libphobos.thread/fiber_guard_page.d
+++ b/libphobos/testsuite/libphobos.thread/fiber_guard_page.d
@@ -1,13 +1,15 @@
 // { dg-options "-O0" }
 // { dg-shouldfail "segv or bus error" }
 import core.thread;
+import core.sys.posix.signal;
 import core.sys.posix.sys.mman;
 
 // this should be true for most architectures
 // (taken from core.thread)
-version = StackGrowsDown;
+version (GNU_StackGrowsDown)
+    version = StackGrowsDown;
 
-enum stackSize = 4096;
+enum stackSize = MINSIGSTKSZ;
 
 // Simple method that causes a stack overflow
 void stackMethod()