Why can't the genesis block be found I create an altcoin? I have built the bitcoin source code with a new pszTimestamp, hashGenesisBlock and hashMerkleRoot

The code builds fine and does not run into any assert problems when validating these hashes on [line 128 and line 129 of chainparams.cpp]. (Great)

However...

When I run bitcoin-qt I run into the error below:

Error: Incorrect or no genesis block found. Wrong datadir for network?

Potential Cause:

Is the reason I am encountering this error because I have not yet mined the genesis block? If so how do I do that? It seems that in the bitcoin code there is nothing about mining the genesis block. I have heard rumours that this functionality was removed and that I will have to download a separate program for this step. Please confirm.
Thant is correct. You have to mine the genesis block first separately if you are compiling the most recent bitcoin codebase. 

Checkout : https://github.com/vlamer/genesis-block-generator