The port needs OpenMP multi processing feature since version 0.37 by default. GCC supports this since version 4.2.
The default CFLAGS are set to compile with OpenMP, but GCC does not have support for it on FreeBSD 6.x and earlier platforms.
I added CFLAGS to deactivate OpenMP directives and linker switches on earlier versions than 7.x.
I also added documentation files to install. It was missing before, and the source contains it anyway.
Fix: Patch attached with submission follows: