nga-c: non-libc: openbsd-amd64 support, source cleanups

FossilOrigin-Name: f8712bb8ce359909a61a8d0ff917173da4e35b8586e34b6207e3604ae40f139e

vm/nga-c-no-libc/Makefile

@@ -1,9 +1,10 @@
 default:
 	@echo specify the target:
-	@echo -  freebsd-x86-32bit
-	@echo -  freebsd-x86-64bit
-	@echo -  macos
-	@echo -  linux-x86-32bit
+	@echo -  freebsd-i386
+	@echo -  freebsd-amd64
+	@echo -  linux-i386
+	@echo -  macos-amd64
+	@echo -  openbsd-amd64
 
 common:
 	mkdir -p bin
@@ -14,22 +15,31 @@ common:
 clean:
 	rm *.o
 
-freebsd-x86-32bit: common
+bsd-i386:
+	nasm -f elf bsd-i386.s
+
+bsd-amd64:
+	nasm -f elf64 bsd-amd64.s
+
+freebsd-i386: common bsd-i386
 	cc -m32 -c retro.c
-	nasm -f elf fbsd.s
-	ld -nostdlib -m elf_i386_fbsd fbsd.o retro.o -o bin/retro.freebsd32
+	ld -nostdlib -m elf_i386_fbsd bsd-i386.o retro.o -o bin/retro
 
-freebsd-x86-64bit: common
+freebsd-amd64: common bsd-amd64
 	cc -m64 -c retro.c
-	nasm -f elf64 fbsd64.s
-	ld -nostdlib -m elf_x86_64_fbsd fbsd64.o retro.o -o bin/retro.freebsd64
+	ld -nostdlib -m elf_x86_64_fbsd bsd-amd64.o retro.o -o bin/retro
 
-macos: common
+openbsd-amd64: common bsd-amd64
 	cc -m64 -c retro.c
+	as openbsd.s -o openbsd.o
+	ld -nostdlib -no-pie -m elf_x86_64 openbsd.o bsd-amd64.o retro.o -o bin/retro
+
+macos-amd64: common
+	cc -m64 -fno-pie -c retro.c
 	nasm -f macho64 macos.s
-	ld macos.o retro.o -o bin/retro.macos
+	ld macos.o retro.o -o bin/retro
 
-linux-x86-32bit: common
+linux-i386: common
 	cc -m32 -c retro.c
 	nasm -f elf linux.s
-	ld -nostdlib linux.o retro.o -o bin/retro.linux32
+	ld -nostdlib linux.o retro.o -o bin/retro

vm/nga-c-no-libc/openbsd.s

@@ -0,0 +1,9 @@
+.section ".note.openbsd.ident", "a"
+        .p2align 2
+        .long   0x8
+        .long   0x4
+        .long   0x1
+        .ascii "OpenBSD\0"
+        .long   0x0
+        .p2align 2
+