Firebird build from master fails on macOS

[Noel Grandin]

On 2018/06/28 11:07 AM, Alexander Thurgood wrote:
> 
> Well, the build seems to be working fine again now, so whatever...
> 
> 

Firebird's makefile is extremely fragile, simply cleaning that folder and trying again normally sorts it out. In extreme 
cases I either disable it, or force a single-threaded compile with

     PARALLELISM=1 make externals