换了msys2后，编译xerces-c-2.8.0，./runConfigure -pmingw-msys -cgcc -xg++ -s -P/opt/xercesc-2.8.0 后遇到如标题所示问题，详下：
checking for unistd.h... yes
checking for XMLByte... no
checking build system type... ./config.guess: unable to guess system type
This script, last modified 2002-07-09, has failed to recognize
the operating system you are using. It is advised that you
download the most up to date version of the config scripts from
ftp://ftp.gnu.org/pub/gnu/config/
If the version you run (./config.guess) is already up to date, please
send the following data and any information you think might be
pertinent to <config-patches@gnu.org> in order to provide the needed
information to handle your system.
config.guess timestamp = 2002-07-09
uname -m = x86_64
uname -r = 2.0.0(0.280/5/3)
uname -s = MINGW64_NT-6.1
uname -v = 2014-11-06 20:34
/usr/bin/uname -p = unknown
/bin/uname -X =
hostinfo =
/bin/universe =
/usr/bin/arch -k =
/bin/arch = x86_64
/usr/bin/oslevel =
/usr/convex/getsysinfo =
UNAME_MACHINE = x86_64
UNAME_RELEASE = 2.0.0(0.280/5/3)
UNAME_SYSTEM = MINGW64_NT-6.1
UNAME_VERSION = 2014-11-06 20:34
configure: error: cannot guess build type; you must specify one
google也说是config.guess比较旧，msys环境编译没有问题，去mingw-w64的svn上拉了个config.guess下来替换掉后问题解决：
checking for stdint.h... yes
checking for unistd.h... yes
checking for XMLByte... no
checking build system type... x86_64-pc-mingw32
checking host system type... x86_64-pc-mingw32
configure: creating ./config.status
config.status: creating Makefile
configure:cannot guess build type; you must specify one
原文地址：http://blog.csdn.net/cuterhei/article/details/41040669
