[coreboot] [help]build cbfstool fail with cygwin64

[Kurt Qiao]

does anyone try cygwin64 to build coreboot in windows7 64bit?
i got fail when build cbfstool with cygwin64.
my steps as below:

1. cygwin64 install utility "patch", "flex", 'wget' etc.

2. git pull latest coreboot from github
build crossgcc
./buildgcc -j 4

3. build iasl
download src from link [1]
make
cp acpica-unix-20150818/generate/unix/bin/iasl /usr/local/bin

4. make menuconfig
choose "emulation/qemu-q35" in my case

5.make
then fail as below
----
<stdout>: In function 'yy_init_buffer':
<stdout>:1395:9: error: implicit declaration of function 'fileno'
[-Werror=implicit-function-declaration]
cc1: all warnings being treated as errors
util/cbfstool/Makefile.inc:59: recipe for target
'build/util/cbfstool/fmd_scanner.o' failed
make: *** [build/util/cbfstool/fmd_scanner.o] Error 1
---

i follow link [2] to modify cbfstool makefile, add _D_GNU_SOURCE for
TOOLCPPFLAGS, CPPFLAGS
and fail as below log.
---
Compilation complete. 0 Errors, 0 Warnings, 0 Remarks, 432 Optimizations
    HOSTCC     cbfstool/fmaptool.o
    HOSTCC     cbfstool/cbfs_sections.o
    HOSTCC     cbfstool/fmap_from_fmd.o
    HOSTCC     cbfstool/fmd.o
    HOSTCC     cbfstool/fmd_parser.o
    HOSTCC     cbfstool/fmd_scanner.o
    HOSTCC     cbfstool/fmap.o
    HOSTCC     cbfstool/kv_pair.o
    HOSTCC     cbfstool/valstr.o
    HOSTCC     cbfstool/fmaptool (link)
build/util/cbfstool/fmd.o:fmd.c:(.text+0xa23): undefined reference to
`yylex_destroy'
build/util/cbfstool/fmd.o:fmd.c:(.text+0xa23): relocation truncated to
fit: R_X86_64_PC32 against undefined symbol `yylex_destroy'
build/util/cbfstool/fmd.o:fmd.c:(.rdata$.refptr.yyin[.refptr.yyin]+0x0):
undefined reference to `yyin'
build/util/cbfstool/fmd_parser.o:fmd_parser.c:(.text+0x386): undefined
reference to `yylex'
build/util/cbfstool/fmd_parser.o:fmd_parser.c:(.text+0x386):
relocation truncated to fit: R_X86_64_PC32 against undefined symbol
`yylex'
collect2: error: ld returned 1 exit status
util/cbfstool/Makefile.inc:83: recipe for target
'build/util/cbfstool/fmaptool' failed
make: *** [build/util/cbfstool/fmaptool] Error 1
---

[1]:https://acpica.org/sites/acpica/files/acpica-unix-20150818.tar.gz
[2]:http://review.coreboot.org/#/c/10027/1