Try removing code marked with "I don't think this is necessary"

src/rt/arch/i386/morestack.S

@@ -213,15 +213,6 @@ MORESTACK:
 
 	popl %ebp
 
-	// FIXME: I don't think these rules are necessary
-	// since the unwinder should never encounter an instruction
-	// pointer pointing here.
-#if defined(__linux__) || defined(__APPLE__) || defined(__FreeBSD__)
-	// Restore the rule for how to find %ebp
-	.cfi_restore %ebp
-	// Tell the unwinder how to find the CFA in terms of %esp
-	.cfi_def_cfa %esp, 16
-#endif
 	retl $8
 
 .L$bail:

src/rt/arch/x86_64/morestack.S

@@ -51,7 +51,7 @@ MORESTACK:
 
         subq $184, %rsp
 
-	// FIXME: libgcc also saves rax. not sure if we need to
+	// FIXME: libgcc also saves rax. not sure if we need to (#2685)
 
 	// Save argument registers of the original function
 	movq %rdi,       (%rsp)
@@ -133,11 +133,6 @@ MORESTACK:
 
 	popq %rax // Restore the return value
 	popq %rbp
-	// FIXME: I don't think these rules are necessary
-	// since the unwinder should never encounter an instruction
-	// pointer pointing here.
-	.cfi_restore %rbp
-	.cfi_def_cfa %rsp, 16
 	ret
 	
 	.cfi_endproc