build: define release package build env; set up nightly regression

_From [derek.br...@gmail.com](https://code.google.com/u/117968039472581148324/) on February 24, 2009 09:50:32_

for a release package we want maximum binary compatibility

we should have a release build setup as a nightly regression to avoid
breaking it (like in issue #35 )

I've been using gcc 4.1.2 with glibc 2.2.5

With more recent toolchain but running on RHEL4 I hit:
> bin/drdeploy -client docs/html/samples/build32/bbsize.so 0x1 "" ls
bin/drdeploy: line 242: 1432 Floating point exception$*

Not sure exactly which fp emulation is being assumed there.

If we use too recent of glibc (2.7+) we end up pulling in:
> nm rel-1.3.2/linux/dynamorio/lib32/release/libdynamorio.so | grep GLIBC
U __isoc99_sscanf@@GLIBC_2.7

And then on an older system we hit:
> bin/drdeploy -client docs/html/samples/build32/bbsize.so 0x1 "" ls
ls: /lib/tls/libc.so.6: version `GLIBC_2.7' not found (required by
/home/derek/rel-1.3.2/dynamorio/lib32/release/libdynamorio.so)

We could avoid the __isoc99_sscanf by defining _GNU_SOURCE, though defined
everywhere we hit issue #34 : probably we could get it to work just defining
around stdio.h. But better to have an older setup in general for
floating-point support, etc.

_Original issue: http://code.google.com/p/dynamorio/issues/detail?id=36_