diff --git a/vendor/luajit/src/lib_io.c b/vendor/luajit/src/lib_io.c
index 04f0f7390..b59d34bfc 100644
--- a/vendor/luajit/src/lib_io.c
+++ b/vendor/luajit/src/lib_io.c
@@ -24,6 +24,16 @@
 #include "lj_ff.h"
 #include "lj_lib.h"
 
+#if LJ_TARGET_WINDOWS
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+
+static int widen(const char *in, wchar_t *out)
+{
+  return MultiByteToWideChar(CP_UTF8, 0, in, -1, out, MAX_PATH);
+}
+#endif
+
 /* Userdata payload for I/O file. */
 typedef struct IOFileUD {
   FILE *fp;		/* File handle. */
@@ -82,7 +92,15 @@ static IOFileUD *io_file_open(lua_State *L, const char *mode)
 {
   const char *fname = strdata(lj_lib_checkstr(L, 1));
   IOFileUD *iof = io_file_new(L);
+#if LJ_TARGET_WINDOWS
+  wchar_t wfname[MAX_PATH];
+  wchar_t wmode[MAX_PATH];
+  if (!widen(fname, wfname) || !widen(mode, wmode))
+    luaL_argerror(L, 1, lj_str_pushf(L, "%s: failed to convert path to utf-16", fname));
+  iof->fp = _wfopen(wfname, wmode);
+#else
   iof->fp = fopen(fname, mode);
+#endif
   if (iof->fp == NULL)
     luaL_argerror(L, 1, lj_str_pushf(L, "%s: %s", fname, strerror(errno)));
   return iof;
@@ -399,7 +417,14 @@ LJLIB_CF(io_open)
   GCstr *s = lj_lib_optstr(L, 2);
   const char *mode = s ? strdata(s) : "r";
   IOFileUD *iof = io_file_new(L);
+#if LJ_TARGET_WINDOWS
+  wchar_t wfname[MAX_PATH];
+  wchar_t wmode[MAX_PATH];
+  if (widen(fname, wfname) && widen(mode, wmode))
+    iof->fp = _wfopen(wfname, wmode);
+#else
   iof->fp = fopen(fname, mode);
+#endif
   return iof->fp != NULL ? 1 : luaL_fileresult(L, 0, fname);
 }
 
@@ -415,7 +440,10 @@ LJLIB_CF(io_popen)
   fflush(NULL);
   iof->fp = popen(fname, mode);
 #else
-  iof->fp = _popen(fname, mode);
+  wchar_t wfname[MAX_PATH];
+  wchar_t wmode[MAX_PATH];
+  if (widen(fname, wfname) && widen(mode, wmode))
+    iof->fp = _wpopen(wfname, wmode);
 #endif
   return iof->fp != NULL ? 1 : luaL_fileresult(L, 0, fname);
 #else
diff --git a/vendor/luajit/unicode-io.patch b/vendor/luajit/unicode-io.patch
new file mode 100644
index 000000000..3dd0d8175
--- /dev/null
+++ b/vendor/luajit/unicode-io.patch
@@ -0,0 +1,64 @@
+diff --git c/vendor/luajit/src/lib_io.c w/vendor/luajit/src/lib_io.c
+index 04f0f73..b59d34b 100644
+--- c/vendor/luajit/src/lib_io.c
++++ w/vendor/luajit/src/lib_io.c
+@@ -24,6 +24,16 @@
+ #include "lj_ff.h"
+ #include "lj_lib.h"
+ 
++#if LJ_TARGET_WINDOWS
++#define WIN32_LEAN_AND_MEAN
++#include <windows.h>
++
++static int widen(const char *in, wchar_t *out)
++{
++  return MultiByteToWideChar(CP_UTF8, 0, in, -1, out, MAX_PATH);
++}
++#endif
++
+ /* Userdata payload for I/O file. */
+ typedef struct IOFileUD {
+   FILE *fp;		/* File handle. */
+@@ -82,7 +92,15 @@ static IOFileUD *io_file_open(lua_State *L, const char *mode)
+ {
+   const char *fname = strdata(lj_lib_checkstr(L, 1));
+   IOFileUD *iof = io_file_new(L);
++#if LJ_TARGET_WINDOWS
++  wchar_t wfname[MAX_PATH];
++  wchar_t wmode[MAX_PATH];
++  if (!widen(fname, wfname) || !widen(mode, wmode))
++    luaL_argerror(L, 1, lj_str_pushf(L, "%s: failed to convert path to utf-16", fname));
++  iof->fp = _wfopen(wfname, wmode);
++#else
+   iof->fp = fopen(fname, mode);
++#endif
+   if (iof->fp == NULL)
+     luaL_argerror(L, 1, lj_str_pushf(L, "%s: %s", fname, strerror(errno)));
+   return iof;
+@@ -399,7 +417,14 @@ LJLIB_CF(io_open)
+   GCstr *s = lj_lib_optstr(L, 2);
+   const char *mode = s ? strdata(s) : "r";
+   IOFileUD *iof = io_file_new(L);
++#if LJ_TARGET_WINDOWS
++  wchar_t wfname[MAX_PATH];
++  wchar_t wmode[MAX_PATH];
++  if (widen(fname, wfname) && widen(mode, wmode))
++    iof->fp = _wfopen(wfname, wmode);
++#else
+   iof->fp = fopen(fname, mode);
++#endif
+   return iof->fp != NULL ? 1 : luaL_fileresult(L, 0, fname);
+ }
+ 
+@@ -415,7 +440,10 @@ LJLIB_CF(io_popen)
+   fflush(NULL);
+   iof->fp = popen(fname, mode);
+ #else
+-  iof->fp = _popen(fname, mode);
++  wchar_t wfname[MAX_PATH];
++  wchar_t wmode[MAX_PATH];
++  if (widen(fname, wfname) && widen(mode, wmode))
++    iof->fp = _wpopen(wfname, wmode);
+ #endif
+   return iof->fp != NULL ? 1 : luaL_fileresult(L, 0, fname);
+ #else