Windowsにhopensslをcabalインストールしようとすると、このエラーが発生します（以下を参照）
注：Windowsにopensslがインストールされており、パスにevp.hがあります
C:/ユーザー/ユーザー名/デスクトップ/src/openssl/0.9.8h/openssl-0.9.8h/outinc/openssl/
インストール時に cabal がパスを認識しないのはなぜですか?
$ cabal install hopenssl \
--extra-include-dirs=C:/Users/username/Desktop/src/openssl/0.9.8h/openssl-0.9.8h/outinc/openssl/ \
--extra-lib-dirs=C:/Users/username/Desktop/src/openssl/0.9.8h/openssl-0.9.8h/outinc/openssl/
cabal.exe: Missing dependency on a foreign library:
* Missing (or bad) header file: openssl/evp.h
This problem can usually be solved by installing the system package that
provides this library (you may need the "-dev" version). If the library is
already installed but in a non-standard location then you can use the flags
--extra-include-dirs= and --extra-lib-dirs= to specify where it is.
If the header file does exist, it may contain errors that are caught by the C
compiler at the preprocessing stage. In this case you can re-run configure
with the verbosity flag -v3 to see the error messages.
cabal.exe: Error: some packages failed to install:
hopenssl-1.6.2 failed during the configure step. The exception was:
ExitFailure 1