Index: /trunk/src/libs/xpcom18a4/nsprpub/pr/src/pthreads/ptthread.c
===================================================================
--- /trunk/src/libs/xpcom18a4/nsprpub/pr/src/pthreads/ptthread.c	(revision 66009)
+++ /trunk/src/libs/xpcom18a4/nsprpub/pr/src/pthreads/ptthread.c	(revision 66010)
@@ -401,5 +401,12 @@
     if (0 == stackSize) stackSize = (64 * 1024);  /* default == 64K */
 #else
-    if (0 == stackSize) stackSize = (2 * 64 * 1024);  /* default == 128K */
+# ifdef RT_ARCH_AMD64
+    /* @bugref{8070}: At least on Mac OS X we run into a stack overflow if we
+     * have to handle many snapshots. Space is not a real concern on 64-bit
+     * hosts. */
+    if (0 == stackSize) stackSize = (512 * 1024);  /* default == 512K */
+# else
+    if (0 == stackSize) stackSize = (128 * 1024);  /* default == 128K */
+# endif
 #endif /* VBOX_USE_IPRT_IN_NSPR */
 #ifdef _MD_MINIMUM_STACK_SIZE