8l: add openbsd

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/4972043

src/cmd/8l/asm.c

@@ -41,6 +41,7 @@
 
 char linuxdynld[] = "/lib/ld-linux.so.2";
 char freebsddynld[] = "/usr/libexec/ld-elf.so.1";
+char openbsddynld[] = "/usr/libexec/ld.so";
 
 int32
 entryvalue(void)
@@ -956,6 +957,9 @@ asmb(void)
 				case Hfreebsd:
 					interpreter = freebsddynld;
 					break;
+				case Hopenbsd:
+					interpreter = openbsddynld;
+					break;
 				}
 			}
 			elfinterp(sh, startva, interpreter);
@@ -1122,7 +1126,10 @@ asmb(void)
 		eh->ident[EI_VERSION] = EV_CURRENT;
 		switch(HEADTYPE) {
 		case Hfreebsd:
-			eh->ident[EI_OSABI] = 9;
+			eh->ident[EI_OSABI] = ELFOSABI_FREEBSD;
+			break;
+		case Hopenbsd:
+			eh->ident[EI_OSABI] = ELFOSABI_OPENBSD;
 			break;
 		}
 

src/cmd/8l/doc.go

@@ -33,6 +33,8 @@ Options new in this version:
 	Write Linux ELF binaries (default when $GOOS is linux)
 -Hfreebsd
 	Write FreeBSD ELF binaries (default when $GOOS is freebsd)
+-Hopenbsd
+	Write OpenBSD ELF binaries (default when $GOOS is openbsd)
 -Hwindows
 	Write Windows PE32 binaries (default when $GOOS is windows)
 -I interpreter

src/cmd/8l/obj.c

@@ -55,6 +55,7 @@ Header headers[] = {
    "darwin", Hdarwin,
    "linux", Hlinux,
    "freebsd", Hfreebsd,
+   "openbsd", Hopenbsd,
    "windows", Hwindows,
    "windowsgui", Hwindows,
    0, 0
@@ -69,6 +70,7 @@ Header headers[] = {
  *	-Hdarwin -Tx -Rx			is Apple Mach-O
  *	-Hlinux -Tx -Rx				is Linux ELF32
  *	-Hfreebsd -Tx -Rx			is FreeBSD ELF32
+ *	-Hopenbsd -Tx -Rx			is OpenBSD ELF32
  *	-Hwindows -Tx -Rx			is MS Windows PE32
  */
 
@@ -223,6 +225,7 @@ main(int argc, char *argv[])
 		break;
 	case Hlinux:	/* elf32 executable */
 	case Hfreebsd:
+	case Hopenbsd:
 		/*
 		 * ELF uses TLS offsets negative from %gs.
 		 * Translate 0(GS) and 4(GS) into -8(GS) and -4(GS).