Update osx build instructions to ensure users link to the correct version of OpenSSL

doc/build-osx.md

@@ -95,6 +95,18 @@ Instructions: HomeBrew
 
         brew install boost miniupnpc openssl berkeley-db4
 
+Note: After you have installed the dependencies, you should check that the Brew installed version of OpenSSL is the one available for compilation. You can check this by typing
+
+        openssl version
+
+into Terminal. You should see OpenSSL 1.0.1e 11 Feb 2013.
+
+If not, you can ensure that the Brew OpenSSL is correctly linked by running
+
+        brew link openssl --force
+
+Rerunning "openssl version" should now return the correct version.
+
 ### Building `bitcoind`
 
 1. Clone the github tree to get the source code and go into the directory.