change env variable name, handle empty string
diff --git a/docs/installation.rst b/docs/installation.rst
index 81e150d..339d8b7 100644
--- a/docs/installation.rst
+++ b/docs/installation.rst
@@ -55,15 +55,15 @@
C:\> pip install cryptography
You can also choose to build statically or dynamically using the
-``PYCA_OPENSSL_INSTALL`` variable. Allowed values are ``static`` (default) and
-``dynamic``.
+``PYCA_WINDOWS_LINK_TYPE`` variable. Allowed values are ``static`` (default)
+and ``dynamic``.
.. code-block:: console
C:\> \path\to\vcvarsall.bat x86_amd64
C:\> set LIB=C:\OpenSSL\lib\VC\static;C:\OpenSSL\lib;%LIB%
C:\> set INCLUDE=C:\OpenSSL\include;%INCLUDE%
- C:\> set PYCA_OPENSSL_INSTALL=dynamic
+ C:\> set PYCA_WINDOWS_LINK_TYPE=dynamic
C:\> pip install cryptography
Building cryptography on Linux