Remove unused elf_machdep.h cruft.

Also add a few missing include guards.

Bug: N/A
Test: builds
Change-Id: I9557303c81a4b11d430112528def038ecb5562a9
diff --git a/libc/arch-x86/include/machine/elf_machdep.h b/libc/arch-x86/include/machine/elf_machdep.h
index 4bce933..5324ebc 100644
--- a/libc/arch-x86/include/machine/elf_machdep.h
+++ b/libc/arch-x86/include/machine/elf_machdep.h
@@ -1,18 +1,7 @@
 /*	$NetBSD: elf_machdep.h,v 1.10 2009/05/30 05:56:52 skrll Exp $	*/
 
-#define	ELF32_MACHDEP_ENDIANNESS	ELFDATA2LSB
-#define	ELF32_MACHDEP_ID_CASES						\
-		case EM_386:						\
-		case EM_486:						\
-			break;
-
-#define	ELF64_MACHDEP_ENDIANNESS	XXX	/* break compilation */
-#define	ELF64_MACHDEP_ID_CASES						\
-		/* no 64-bit ELF machine types supported */
-
-#define	ELF32_MACHDEP_ID		EM_386
-
-#define ARCH_ELFSIZE		32	/* MD native binary size */
+#ifndef _X86_ELF_MACHDEP_H_
+#define _X86_ELF_MACHDEP_H_
 
 /* i386 relocations */
 #define	R_386_NONE	0
@@ -62,3 +51,5 @@
 #define	R_386_IRELATIVE		42
 
 #define	R_TYPE(name)	__CONCAT(R_386_,name)
+
+#endif