python – 在pkg-config搜索路径REDHAT6.5中找不到包libffi

我正在尝试运行与专有软件安装相关的setup.py,它依赖于libffi.

从它的Redhat 6.5开始,python版本为2.6,我安装了python 2.7.

libffi已经安装,当我创建virtualenv并尝试通过运行setup.py安装软件时,我收到以下错误：

No package 'libffi' found
Package libffi was not found in the pkg-config search path.
Perhaps you should add the directory containing `libffi.pc'
to the PKG_CONfig_PATH environment variable
No package 'libffi' found
c/_cffi_BACkend.c:15:17: error: ffi.h: No such file or directory
In file included from c/_cffi_BACkend.c:63:

yum list libffi
Loaded plugins: product-id,refresh-packagekit,security,subscription-manager
This system is not registered to Red Hat Subscription Management. You can use subscription-manager to register.
Installed Packages
libffi.x86_64                  3.0.5-3.2.el6                   @anaconda-RedHatEnterpriseLinux-201311111358.x86_64/6.5
Available Packages
libffi.i686                    3.0.5-3.2.el6                   rHel-local   

我的查询是如何修改pkg-config搜索路径.
指向libffi.pc？