参考：http://trac.osgeo.org/gdal/ticket/6077
参考：http://stackoverflow.com/questions/5560132/syntax-error-near-unexpected-token
参考：https://segmentfault.com/a/1190000004592973

当执行：

make

报错：

...
./configure: line 16651: syntax error near unexpected token `0.20'
./configure: line 16651: `PKG_PROG_PKG_CONFIG(0.20)'

查看pkg-config版本：

pkg-config --version

输出：

0.23

PKG_PROG_PKG_CONFIG([MIN-VERSION])：定位 pkg-config 工具在系统中的位置，并检测其版本的兼容性。

aclocal.m4 included in wslay distribution includes definition of PKG_PROG_PKG_CONFIG, so it should work. It is true that pkg-config binary is required.

运行：

ACLOCAL_PATH=/usr/local/share/aclocal

export ACLOCAL_PATH=”/usr/share/aclocal/:/usr/local/share/aclocal” export OPENSSL_CFLAGS=”-I/usr/local/ssl/include” OPENSSL_LIBS=”-L/usr/local/ssl/lib -lssl -lcrypto” CUNIT_CFLAGS=”-I/usr/include/CUnit” CUNIT_LIBS=”-L/usr/lib -lcunit” LIBEVENT_OPENSSL_CFLAGS=”-I/usr/include/event2″ LIBEVENT_OPENSSL_LIBS=”-L/usr/lib -levent”

参考：https://groups.google.com/forum/#!topic/mailing.freebsd.ports/x8dr9mf9itM
参考：https://github.com/texane/stlink/issues/83

升级pkg-config？参考：https://amon.org/pkg-config

还是没能解决。