Added a SVR4 port

```yaml:frontmatter

below my signature, there are a coupls of diffs and files in a shell
archive, which were needed to build postgres95 1.02 on Siemens Nixdorfs
MIPS based SINIX systems. Except for the compiler switches "-W0" and
"-LD-Blargedynsym" these diffs should also apply for other SVR4 based
systems. The changes in "Makefile.global" and "genbki.sh" can probably
be ignored (I needed gawk, to make the script run).

There is one bugfix thou. In "src/backend/parser/sysfunc.c" the
function in this file didn't honor the EUROPEAN_DATES ifdef.

```

Submitted by:  Frank Ridderbusch <ridderbusch.pad@sni.de>