Fix DragonFly build (unsupported).

Thanks to Robin Hahling, Alex Hornung and Joris Giovannangeli.

src/jit/bcsave.lua

@@ -69,7 +69,7 @@ local map_arch = {
 
 local map_os = {
   linux = true, windows = true, osx = true, freebsd = true, netbsd = true,
-  openbsd = true, solaris = true,
+  openbsd = true, dragonfly = true, solaris = true,
 }
 
 local function checkarg(str, map, err)

src/lj_alloc.c

@@ -194,14 +194,14 @@ static LJ_AINLINE void *CALL_MMAP(size_t size)
   return ptr;
 }
 
-#elif LJ_TARGET_OSX || LJ_TARGET_PS4 || defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__sun__)
+#elif LJ_TARGET_OSX || LJ_TARGET_PS4 || defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) || defined(__sun__)
 
 /* OSX and FreeBSD mmap() use a naive first-fit linear search.
 ** That's perfect for us. Except that -pagezero_size must be set for OSX,
 ** otherwise the lower 4GB are blocked. And the 32GB RLIMIT_DATA needs
 ** to be reduced to 250MB on FreeBSD.
 */
-#if LJ_TARGET_OSX
+#if LJ_TARGET_OSX || defined(__DragonFly__)
 #define MMAP_REGION_START	((uintptr_t)0x10000)
 #elif LJ_TARGET_PS4
 #define MMAP_REGION_START	((uintptr_t)0x4000)
@@ -238,7 +238,7 @@ static LJ_AINLINE void *CALL_MMAP(size_t size)
       return p;
     }
     if (p != CMFAIL) munmap(p, size);
-#ifdef __sun__
+#if defined(__sun__) || defined(__DragonFly__)
     alloc_hint += 0x1000000;  /* Need near-exhaustive linear scan. */
     if (alloc_hint + size < MMAP_REGION_END) continue;
 #endif

src/lj_arch.h

@@ -67,7 +67,8 @@
 #elif defined(__MACH__) && defined(__APPLE__)
 #define LUAJIT_OS	LUAJIT_OS_OSX
 #elif (defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || \
-       defined(__NetBSD__) || defined(__OpenBSD__)) && !defined(__ORBIS__)
+       defined(__NetBSD__) || defined(__OpenBSD__) || \
+       defined(__DragonFly__)) && !defined(__ORBIS__)
 #define LUAJIT_OS	LUAJIT_OS_BSD
 #elif (defined(__sun__) && defined(__svr4__)) || defined(__CYGWIN__)
 #define LUAJIT_OS	LUAJIT_OS_POSIX

src/lj_gdbjit.c

@@ -356,6 +356,8 @@ static const ELFheader elfhdr_template = {
   .eosabi = 2,
 #elif defined(__OpenBSD__)
   .eosabi = 12,
+#elif defined(__DragonFly__)
+  .eosabi = 0,
 #elif (defined(__sun__) && defined(__svr4__))
   .eosabi = 6,
 #else