It was removed in hrev55422 as we never had declared it in any headers.
But it seems some software came to depend on it anyway. Reinstate it,
and add a declaration for it, behind _GNU_SOURCE.
Cleaned up some header style violations, making sure there are two blank lines after the header guards.
This fixes the posix header part of #2191.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@39288 a95241bf-73f2-0310-859d-f6bbb57e9c96
* It was not self containing, as it used size_t without defining it.
* It was not C++ safe.
* It used the restrict keyword that is not recognized in GCC2. This fixes bug
#2262.
* It did not contain parameter names as demanded by our coding style.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@25818 a95241bf-73f2-0310-859d-f6bbb57e9c96
