lib_jit.c: Add 'jit.auditlog(filename)' Lua API function

Supports opening the auditlog from Lua. Note that the log always
includes every entry since the process started (even if opened late.)

src/lib_jit.c

@@ -28,6 +28,7 @@
 #include "lj_dispatch.h"
 #include "lj_vm.h"
 #include "lj_lib.h"
+#include "lj_auditlog.h"
 
 #include "luajit.h"
 
@@ -80,6 +81,19 @@ LJLIB_CF(jit_flush)
   return setjitmode(L, LUAJIT_MODE_FLUSH);
 }
 
+LJLIB_CF(jit_auditlog)
+{
+  if (L->base < L->top && tvisstr(L->base)) {
+    if (lj_auditlog_open(strdata(lj_lib_checkstr(L, 1)))) {
+      return 0;
+    } else {
+      lj_err_caller(L, LJ_ERR_AUDITLOG);
+    }
+  } else {
+    lj_err_argtype(L, 1, "string filename");
+  }
+}
+
 /* Push a string for every flag bit that is set. */
 static void flagbits_to_strings(lua_State *L, uint32_t flags, uint32_t base,
 				const char *str)

src/lj_errmsg.h

@@ -99,6 +99,7 @@ ERRDEF(BADMODN,	"name conflict for module " LUA_QS)
 ERRDEF(JITPROT,	"runtime code generation failed, restricted kernel?")
 ERRDEF(NOJIT,	"JIT compiler disabled, CPU does not support SSE2")
 ERRDEF(JITOPT,	"unknown or malformed optimization flag " LUA_QS)
+ERRDEF(AUDITLOG,"auditlog could not be opened")
 
 /* Lexer/parser errors. */
 ERRDEF(XMODE,	"attempt to load chunk with wrong mode")