Docs: Add disable-wallet section to OSX build instructions

Author: bitstein

doc/build-osx.md

@@ -64,6 +64,18 @@ Build Bitcoin Core
 
         make deploy
 
+Disable-wallet mode
+--------------------
+When the intention is to run only a P2P node without a wallet, Bitcoin Core may be compiled in
+disable-wallet mode with:
+
+    ./configure --disable-wallet
+
+In this case there is no dependency on Berkeley DB 4.8.
+
+Mining is also possible in disable-wallet mode, but only using the `getblocktemplate` RPC
+call not `getwork`.
+
 Running
 -------