Move stack out to separate object, so that having a stack doesn't drag in

setup.S.

src/arch/i386/core/setup.S

 	popfl
 	lret
 
-/****************************************************************************
- * Internal stack
- ****************************************************************************
- */
-	.section ".stack"
-	.align 8
-_stack:
-	.space 4096
-_estack:

src/arch/i386/core/stack.S

+	.arch i386
+
+/****************************************************************************
+ * Internal stack
+ ****************************************************************************
+ */
+	.section ".stack"
+	.align 8
+	.globl _stack
+_stack:
+	.space 4096
+	.globl _estack
+_estack: