我无法使用 ruby1.8.6 p111 在 Windows 7 x64 上安装遏制：
ruby extconf.rb install curb-0.8.1.gem -- --with-curl-dir=C:\curl-7.26.0
checking for curl-config... no
checking for main() in curl.lib... no
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of
necessary libraries and/or headers. Check the mkmf.log file for more
details. You may need configuration options.
Provided configuration options:
--with-opt-dir
--without-opt-dir
--with-opt-include
--without-opt-include=${opt-dir}/include
--with-opt-lib
--without-opt-lib=${opt-dir}/lib
--with-make-prog
--srcdir=.
--curdir
--ruby=C:/Ruby186/bin/ruby
--with-curl-dir
--with-curl-include
--without-curl-include=${curl-dir}/include
--with-curl-lib
--without-curl-lib=${curl-dir}/lib
--with-curllib
--without-curllib
extconf.rb:18: Can't find libcurl or curl/curl.h (RuntimeError)
Try passing --with-curl-dir or --with-curl-lib and --with-curl-include options to extconf.
为了澄清，C:\curl-7.26.0是一个带有文件夹的libcurl v7.26.0lib/bin/include。
我错过了什么？