-Wl,-z,noexecstack hack removed for Linux and FreeBSD

The fix for <http://qa.openoffice.org/issues/show_bug.cgi?id=110197> 
"solenv: remove -Wl,-z,noexecstack hack," on CWS sb126 targeting OOo 
3.4, removes from the OOo code base virtually all mentions of 
noexecstack (see issue for details).  Most mentions were in Linux-only 
code (where the need for the hack was probably only motivated by the old 
Sun Hamburg tool chain, and so the hack is no longer needed after the 
recent upgrade of that tool chain).

But some mentions were in code relevant for Linux and FreeBSD.  I assume 
that this was by accident rather than by design, and the 
-Wl,-z,noexecstack was never really necessary on FreeBSD (and it was 
just lumped together with other pieces of code that actually are 
relevant on both platforms).

Let me know if this change causes any problems,

-Stephan