x86_64/elf_machdep.h: Replace stub with NetBSD version

The other ports included that architecture's version of this file from
NetBSD. This patch follows that pattern.

closes #4641

cpukit/score/cpu/x86_64/include/machine/elf_machdep.h

@@ -1,4 +1,76 @@
-/*
- * XXX: Needs research as to purpose. Seems like this might do:
- * https://github.com/NetBSD/src/blob/trunk/sys/arch/amd64/include/elf_machdep.h
- */
+/*	$NetBSD: elf_machdep.h,v 1.4.18.1 2017/12/03 11:35:47 jdolecek Exp $	*/
+
+#if !defined __i386__
+
+#define	ELF32_MACHDEP_ENDIANNESS	ELFDATA2LSB
+#define	ELF32_MACHDEP_ID_CASES						\
+		case EM_386:						\
+			break;
+
+#define	ELF64_MACHDEP_ENDIANNESS	ELFDATA2LSB
+#define	ELF64_MACHDEP_ID_CASES						\
+		case EM_X86_64:						\
+			break;
+
+#define	ELF32_MACHDEP_ID	EM_386
+#define	ELF64_MACHDEP_ID	EM_X86_64
+
+#define	KERN_ELFSIZE		64
+#define ARCH_ELFSIZE		64	/* MD native binary size */
+
+/* x86-64 relocations */
+
+#define R_X86_64_NONE		0
+#define R_X86_64_64		1
+#define R_X86_64_PC32		2
+#define R_X86_64_GOT32		3
+#define R_X86_64_PLT32		4
+#define R_X86_64_COPY		5
+#define R_X86_64_GLOB_DAT	6
+#define R_X86_64_JUMP_SLOT	7
+#define R_X86_64_RELATIVE	8
+#define R_X86_64_GOTPCREL	9
+#define R_X86_64_32		10
+#define R_X86_64_32S		11
+#define R_X86_64_16		12
+#define R_X86_64_PC16		13
+#define R_X86_64_8		14
+#define R_X86_64_PC8		15
+
+/* TLS relocations */
+#define R_X86_64_DTPMOD64	16
+#define R_X86_64_DTPOFF64	17
+#define R_X86_64_TPOFF64	18
+#define R_X86_64_TLSGD		19
+#define R_X86_64_TLSLD		20
+#define R_X86_64_DTPOFF32	21
+#define R_X86_64_GOTTPOFF	22
+#define R_X86_64_TPOFF32	23
+
+#define R_X86_64_PC64		24
+#define R_X86_64_GOTOFF64	25
+#define R_X86_64_GOTPC32	26
+#define R_X86_64_GOT64		27
+#define R_X86_64_GOTPCREL64	28
+#define R_X86_64_GOTPC64	29
+#define R_X86_64_GOTPLT64	30
+#define R_X86_64_PLTOFF64	31
+#define R_X86_64_SIZE32		32
+#define R_X86_64_SIZE64		33
+#define R_X86_64_GOTPC32_TLSDESC 34
+#define R_X86_64_TLSDESC_CALL	35
+#define R_X86_64_TLSDESC	36
+#define R_X86_64_IRELATIVE	37
+#define R_X86_64_RELATIVE64	38
+#define R_X86_64_PC32_BND	39
+#define R_X86_64_PLT32_BND	40
+#define R_X86_64_GOTPCRELX	41
+#define R_X86_64_REX_GOTPCRELX	42
+
+#define	R_TYPE(name)	__CONCAT(R_X86_64_,name)
+
+#else	/*	!__i386__	*/
+
+#include <i386/elf_machdep.h>
+
+#endif	/*	!__i386__	*/