It's worse still. Even on a Linux system with GNU tools, the slightest deviation from the author's system causes "interesting" failures. One recent one I encountered was glibc refusing to build with GNU binutils 2.20. The configure script was looking for a version of 2.1[3-9] and complained about it being too old otherwise. Then there is the whole cross-compiling issue.
The above notwithstanding, BSD people ought really think twice before opening their mouths. They have one of the most broken systems I know of, missing a huge number of standard (as in POSIX/SUS) features. Some of their system headers even refuse to compile without extra compiler flags.