update documentation

change variable names to disable or enable microhttpd and OpenSSL

README.md

@@ -168,12 +168,12 @@ and install.
 -`CMAKE_BUILD_TYPE` set the build type
   - valid options: `Release` or `Debug`
   - you should always keep `Release` for your productive miners
-- `MICROHTTPD_REQUIRED` allow to disable/enable the dependency *microhttpd*
+- `MICROHTTPD_ENABLE` allow to disable/enable the dependency *microhttpd*
   - by default enabled
-  - there is no *http* interface available if option is disabled: `cmake . -DMICROHTTPD_REQUIRED=OFF`
-- `OpenSSL_REQUIRED`allow to disable/enable the dependency *OpenSSL*
+  - there is no *http* interface available if option is disabled: `cmake . -DMICROHTTPD_ENABLE=OFF`
+- `OpenSSL_ENABLE`allow to disable/enable the dependency *OpenSSL*
   - by default enabled
-  - it is not possible to connect to a *https* secured pool if optin is disabled: `cmake . -DOpenSSL_REQUIRED=OFF`
+  - it is not possible to connect to a *https* secured pool if optin is disabled: `cmake . -DOpenSSL_ENABLE=OFF`
 
 ## PGP Key
 ```