diff --git a/ext/fiddle/win32/fficonfig.h b/ext/fiddle/win32/fficonfig.h
deleted file mode 100644
index 776808159c9dee..00000000000000
--- a/ext/fiddle/win32/fficonfig.h
+++ /dev/null
@@ -1,29 +0,0 @@
-#define HAVE_ALLOCA 1
-#define HAVE_MEMCPY 1
-#define HAVE_MEMORY_H 1
-#define HAVE_STDLIB_H 1
-#define HAVE_STRING_H 1
-#define HAVE_SYS_STAT_H 1
-#define HAVE_SYS_TYPES_H 1
-#if _MSC_VER >= 1600
-#define HAVE_INTTYPES_H 1
-#define HAVE_STDINT_H 1
-#endif
-
-#define SIZEOF_DOUBLE 8
-#if defined(X86_WIN64)
-#define SIZEOF_SIZE_T 8
-#else
-#define SIZEOF_SIZE_T 4
-#endif
-
-#define STACK_DIRECTION -1
-
-#define STDC_HEADERS 1
-
-#ifdef LIBFFI_ASM
-#define FFI_HIDDEN(name)
-#else
-#define FFI_HIDDEN
-#endif
-
diff --git a/ext/fiddle/win32/libffi-3.2.1-mswin.patch b/ext/fiddle/win32/libffi-3.2.1-mswin.patch
deleted file mode 100644
index f9100e703db581..00000000000000
--- a/ext/fiddle/win32/libffi-3.2.1-mswin.patch
+++ /dev/null
@@ -1,191 +0,0 @@
-diff -ru libffi-3.2.1/src/x86/ffi.c libffi-3.2.1/src/x86/ffi.c
---- libffi-3.2.1/src/x86/ffi.c	2014-11-08 21:47:24.000000000 +0900
-+++ libffi-3.2.1/src/x86/ffi.c	2014-12-25 18:46:14.806761900 +0900
-@@ -99,11 +99,13 @@
-        i != 0;
-        i--, p_arg += dir, p_argv += dir)
-     {
-+      size_t z;
-+
-       /* Align if necessary */
-       if ((sizeof(void*) - 1) & (size_t) argp)
-         argp = (char *) ALIGN(argp, sizeof(void*));
- 
--      size_t z = (*p_arg)->size;
-+      z = (*p_arg)->size;
- 
- #ifdef X86_WIN64
-       if (z > FFI_SIZEOF_ARG
-@@ -202,6 +204,7 @@
-      on top of stack, so that those can be moved to registers by call-handler.  */
-   if (stack_args_count > 0)
-     {
-+      int i;
-       if (dir < 0 && stack_args_count > 1)
-         {
-           /* Reverse order if iterating arguments backwards */
-@@ -210,7 +213,6 @@
-           *(ffi_arg*) p_stack_data[stack_args_count - 1] = tmp;
-         }
-       
--      int i;
-       for (i = 0; i < stack_args_count; i++)
-         {
-           if (p_stack_data[i] != argp2)
-@@ -569,11 +571,12 @@
-        i < cif->nargs && passed_regs < max_stack_count;
-        i++, p_arg++)
-     {
-+      size_t sz;
-       if ((*p_arg)->type == FFI_TYPE_FLOAT
-          || (*p_arg)->type == FFI_TYPE_STRUCT)
-         continue;
- 
--      size_t sz = (*p_arg)->size;
-+      sz = (*p_arg)->size;
-       if(sz == 0 || sz > FFI_SIZEOF_ARG)
-         continue;
- 
-@@ -599,11 +602,13 @@
-        i != 0;
-        i--, p_arg += dir, p_argv += dir)
-     {
-+      size_t z;
-+
-       /* Align if necessary */
-       if ((sizeof(void*) - 1) & (size_t) argp)
-         argp = (char *) ALIGN(argp, sizeof(void*));
- 
--      size_t z = (*p_arg)->size;
-+      z = (*p_arg)->size;
- 
- #ifdef X86_WIN64
-       if (z > FFI_SIZEOF_ARG
-@@ -642,7 +647,7 @@
- #endif
-     }
- 
--  return (size_t)argp - (size_t)stack;
-+  return (int)((size_t)argp - (size_t)stack);
- }
- 
- #define FFI_INIT_TRAMPOLINE_WIN64(TRAMP,FUN,CTX,MASK) \
-@@ -855,11 +860,12 @@
-   
-   for (i = 0; i < cif->nargs && passed_regs <= max_regs; i++)
-     {
-+      size_t sz;
-       if (cif->arg_types[i]->type == FFI_TYPE_FLOAT
-          || cif->arg_types[i]->type == FFI_TYPE_STRUCT)
-         continue;
- 
--      size_t sz = cif->arg_types[i]->size;
-+      sz = cif->arg_types[i]->size;
-       if (sz == 0 || sz > FFI_SIZEOF_ARG)
-         continue;
- 
-diff -ru libffi-3.2.1/src/x86/ffitarget.h libffi-3.2.1/src/x86/ffitarget.h
---- libffi-3.2.1/src/x86/ffitarget.h	2014-11-08 21:47:24.000000000 +0900
-+++ libffi-3.2.1/src/x86/ffitarget.h	2014-12-22 15:45:54.000000000 +0900
-@@ -50,7 +50,9 @@
- #endif
- 
- #define FFI_TARGET_SPECIFIC_STACK_SPACE_ALLOCATION
-+#ifndef _MSC_VER
- #define FFI_TARGET_HAS_COMPLEX_TYPE
-+#endif
- 
- /* ---- Generic type definitions ----------------------------------------- */
- 
-diff -ru libffi-3.2.1/src/x86/win64.S libffi-3.2.1/src/x86/win64.S
---- libffi-3.2.1/src/x86/win64.S	2014-11-08 21:47:24.000000000 +0900
-+++ libffi-3.2.1/src/x86/win64.S	2014-12-22 16:14:40.000000000 +0900
-@@ -127,7 +127,7 @@
- 
- 	mov	rcx, QWORD PTR RVALUE[rbp]
- 	mov	DWORD PTR [rcx], eax
--	jmp	ret_void$
-+	jmp	SHORT ret_void$
- 
- ret_struct2b$:
-  	cmp	DWORD PTR CIF_FLAGS[rbp], FFI_TYPE_SMALL_STRUCT_2B
-@@ -135,7 +135,7 @@
- 
- 	mov	rcx, QWORD PTR RVALUE[rbp]
- 	mov	WORD PTR [rcx], ax
--	jmp	ret_void$
-+	jmp	SHORT ret_void$
- 
- ret_struct1b$:
-  	cmp	DWORD PTR CIF_FLAGS[rbp], FFI_TYPE_SMALL_STRUCT_1B
-@@ -143,7 +143,7 @@
- 
- 	mov	rcx, QWORD PTR RVALUE[rbp]
- 	mov	BYTE PTR [rcx], al
--	jmp	ret_void$
-+	jmp	SHORT ret_void$
- 
- ret_uint8$:
-  	cmp	DWORD PTR CIF_FLAGS[rbp], FFI_TYPE_UINT8
-@@ -152,7 +152,7 @@
- 	mov	rcx, QWORD PTR RVALUE[rbp]
- 	movzx   rax, al
- 	mov	QWORD PTR [rcx], rax
--	jmp	ret_void$
-+	jmp	SHORT ret_void$
- 
- ret_sint8$:
-  	cmp	DWORD PTR CIF_FLAGS[rbp], FFI_TYPE_SINT8
-@@ -161,7 +161,7 @@
- 	mov	rcx, QWORD PTR RVALUE[rbp]
- 	movsx   rax, al
- 	mov	QWORD PTR [rcx], rax
--	jmp	ret_void$
-+	jmp	SHORT ret_void$
- 
- ret_uint16$:
-  	cmp	DWORD PTR CIF_FLAGS[rbp], FFI_TYPE_UINT16
-@@ -188,7 +188,13 @@
- 	mov	rcx, QWORD PTR RVALUE[rbp]
- 	mov     eax, eax
- 	mov	QWORD PTR [rcx], rax
--	jmp	SHORT ret_void$
-+
-+ret_void$:
-+	xor	rax, rax
-+
-+	lea	rsp, QWORD PTR [rbp+16]
-+	pop	rbp
-+	ret	0
- 
- ret_sint32$:
-  	cmp	DWORD PTR CIF_FLAGS[rbp], FFI_TYPE_SINT32
-@@ -247,13 +253,6 @@
- 	cdqe
- 	mov	QWORD PTR [rcx], rax
-  	jmp	SHORT ret_void$
--
--ret_void$:
--	xor	rax, rax
--
--	lea	rsp, QWORD PTR [rbp+16]
--	pop	rbp
--	ret	0
- ffi_call_win64 ENDP
- _TEXT	ENDS
- END
-diff -ru libffi-3.2.1/include/ffi.h.in libffi-3.2.1/include/ffi.h.in
---- libffi-3.2.1/include/ffi.h.in	2014-11-08 21:47:24.000000000 +0900
-+++ libffi-3.2.1/include/ffi.h.in	2015-01-11 12:35:30.000000000 +0900
-@@ -103,6 +103,11 @@
- #   undef  FFI_64_BIT_MAX
- #   define FFI_64_BIT_MAX 9223372036854775807LL
- #  endif
-+#  ifdef _MSC_VER
-+#   define FFI_LONG_LONG_MAX _I64_MAX
-+#   undef  FFI_64_BIT_MAX
-+#   define FFI_64_BIT_MAX 9223372036854775807I64
-+#  endif
- # endif
- #endif
- 
diff --git a/ext/fiddle/win32/libffi-config.rb b/ext/fiddle/win32/libffi-config.rb
deleted file mode 100755
index 8e8069a943a518..00000000000000
--- a/ext/fiddle/win32/libffi-config.rb
+++ /dev/null
@@ -1,48 +0,0 @@
-#!/usr/bin/ruby
-# frozen_string_literal: true
-require 'fileutils'
-
-basedir = File.dirname(__FILE__)
-conf = {}
-enable = {}
-until ARGV.empty?
-  arg = ARGV.shift
-  case arg
-  when '-C'
-    # ignore
-  when /\A--srcdir=(.*)/
-    conf['SRCDIR'] = srcdir = $1
-  when /\A(CC|CFLAGS|CXX|CXXFLAGS|LD|LDFLAGS)=(.*)/
-    conf[$1] = $2
-  when /\A--host=(.*)/
-    host = $1
-  when /\A--enable-([^=]+)(?:=(.*))?/
-    enable[$1] = $2 || true
-  when /\A--disable-([^=]+)/
-    enable[$1] = false
-  end
-end
-
-File.foreach("#{srcdir}/configure.ac") do |line|
-  if /^AC_INIT\((.*)\)/ =~ line
-    version = $1.split(/,\s*/)[1]
-    version.gsub!(/\A\[|\]\z/, '')
-    conf['VERSION'] = version
-    break
-  end
-end
-
-builddir = srcdir == "." ? (enable['builddir'] || ".") : "."
-conf['TARGET'] = /^x64/ =~ host ? "X86_WIN64" : "X86_WIN32"
-
-FileUtils.mkdir_p([builddir, "#{builddir}/include", "#{builddir}/src/x86"])
-FileUtils.cp("#{basedir}/fficonfig.h", ".", preserve: true)
-
-hdr = File.binread("#{srcdir}/include/ffi.h.in")
-hdr.gsub!(/@(\w+)@/) {conf[$1] || $&}
-hdr.gsub!(/^(#if\s+)@\w+@/, '\10')
-File.binwrite("#{builddir}/include/ffi.h", hdr)
-
-mk = File.binread("#{basedir}/libffi.mk.tmpl")
-mk.gsub!(/@(\w+)@/) {conf[$1] || $&}
-File.binwrite("Makefile", mk)
diff --git a/ext/fiddle/win32/libffi.mk.tmpl b/ext/fiddle/win32/libffi.mk.tmpl
deleted file mode 100644
index 2a16e8efec6ab8..00000000000000
--- a/ext/fiddle/win32/libffi.mk.tmpl
+++ /dev/null
@@ -1,96 +0,0 @@
-# -*- makefile -*-
-# ====================================================================
-#
-# libffi Windows Makefile
-#
-#
-# ====================================================================
-#
-NAME	= ffi
-TARGET	= @TARGET@
-CC	= cl
-!if "$(TARGET)" == "X86_WIN64"
-AS	= ml64
-!else
-AS	= ml
-!endif
-AR	= link
-DLEXT	= dll
-OBJEXT	= obj
-LIBEXT	= lib
-TOPDIR	= @SRCDIR@
-CPP	= $(CC) -EP
-CFLAGS	= @CFLAGS@
-ARFLAGS	= -lib
-ASFLAGS	= -coff -W3 -Cx
-INCLUDES= -I. -I./include -I./src/x86 \
-	  -I$(TOPDIR)/include -I$(TOPDIR)/include/src/x86
-
-SRCDIR	= $(TOPDIR)/src
-WORKDIR	= ./.libs
-BUILDDIR= ./src
-LIBNAME	= lib$(NAME)
-STATICLIB= $(WORKDIR)/$(LIBNAME)_convenience.$(LIBEXT)
-
-HEADERS = \
-	./fficonfig.h
-FFI_HEADERS = \
-	./include/ffi.h \
-	./include/ffitarget.h
-
-!if "$(TARGET)" == "X86_WIN32"
-OSSRC	= win32
-!else if "$(TARGET)" == "X86_WIN64"
-OSSRC	= win64
-!else
-! error unknown target: $(TARGET)
-!endif
-
-OBJECTS = \
-	$(BUILDDIR)/closures.$(OBJEXT) \
-	$(BUILDDIR)/debug.$(OBJEXT) \
-	$(BUILDDIR)/java_raw_api.$(OBJEXT) \
-	$(BUILDDIR)/prep_cif.$(OBJEXT) \
-	$(BUILDDIR)/raw_api.$(OBJEXT) \
-	$(BUILDDIR)/types.$(OBJEXT) \
-	$(BUILDDIR)/x86/ffi.$(OBJEXT) \
-	$(BUILDDIR)/x86/$(OSSRC).$(OBJEXT)
-ASMSRCS = \
-	$(BUILDDIR)/x86/$(OSSRC).asm
-
-.SUFFIXES : .S .asm
-
-all: $(WORKDIR) $(STATICLIB)
-
-{$(SRCDIR)}.c{$(BUILDDIR)}.$(OBJEXT):
-	$(CC) -c $(CFLAGS) $(INCLUDES) -Fo$(@:\=/) -Fd$(WORKDIR)/$(NAME)-src $(<:\=/)
-
-{$(SRCDIR)/x86}.c{$(BUILDDIR)/x86}.$(OBJEXT):
-	$(CC) -c $(CFLAGS) $(INCLUDES) -Fo$(@:\=/) -Fd$(WORKDIR)/$(NAME)-src $(<:\=/)
-
-{$(SRCDIR)/x86}.S{$(BUILDDIR)/x86}.asm:
-	$(CPP) $(CFLAGS) $(INCLUDES) $(<:\=/) >$(@:\=/)
-
-{$(BUILDDIR)/x86}.asm{$(BUILDDIR)/x86}.$(OBJEXT):
-	cd $(@D) && $(AS) -c $(ASFLAGS) -Fo $(@F) $(<F)
-
-$(BUILDDIR)/x86/$(OSSRC).asm: $(SRCDIR)/x86/$(OSSRC).S
-
-$(OBJECTS): $(FFI_HEADERS) $(HEADERS)
-
-$(WORKDIR):
-	-@if not exist "$(WORKDIR:/=\)\$(NULL)" mkdir $(WORKDIR:/=\)
-
-$(STATICLIB): $(WORKDIR) $(OBJECTS)
-	$(AR) $(ARFLAGS) -out:$(STATICLIB) @<<
-	$(OBJECTS)
-<<
-
-clean:
-	-@del /Q $(OBJECTS:/=\) 2>NUL
-	-@del /Q $(ASMSRCS:/=\) 2>NUL
-	-@del /Q /S $(WORKDIR:/=\) 2>NUL
-
-distclean: clean
-	-@del /Q $(HEADERS:/=\) $(FFI_HEADERS:/=\) 2>NUL
-	-@del /Q Makefile 2>NUL