[Rd] I have finished compiling of R 64 bit on 64 bit Windows use MINGW64

[Gong Yu]

dear prof brian :
I saw the svn changes ,but i think src\xz\makefile.win maybe not correct at

ifeq ($(strip $(WIN)),64)
OBJECTS = $(SOURCES:.c=.o) crc32_x86.o crc64_x86.o
else
OBJECTS = $(SOURCES:.c=.o) crc32_fast.o crc64_fast.o
endif

should be

ifeq ($(strip $(WIN)),32)
OBJECTS = $(SOURCES:.c=.o) crc32_x86.o crc64_x86.o
else
OBJECTS = $(SOURCES:.c=.o) crc32_fast.o crc64_fast.o
endif

because gcc64 can't compile crc32_x86.s crc64_x86.s,but gcc 32 can ,
so gcc64 must compile the  crc32_fast.c crc64_fast.c

best wishs
Gong Yu