libgcrypt compiles fine on regular FreeBSD 10.1 with the proper
architecture. The problem with the mismatched architecture was because
I was on a virtual machine and I had to run a 32 bit OS in the machine
because my 64-bit hardware didn't have hardware virtualization and
would only run a 32-bit OS. I guess that situation isn't too common,
but I'll leave it to you to classify the original report as a bug or
converted feature request/idea.

This is related to the "ALIGN (3)" mpi code that caused a compile
problem on FreeBSD 10.1 (I changed it to "ALIGN (2)" and it compiled,
but I'm not sure if that will break something).