DSO leak

[ZIGLIO, Frediano, VF-IT]

Well, I think that Dirk Stoecker's patch to fix leak on
loading/unloading libgcrypt is useful (at least for me). I work on
FreeTDS project. This project provide some driver to dialog with
Microsoft SQL Server (mssql) database. Well... where does libgcrypt came
into this? We use GnuTLS to open a SSL connection to mssql. GnuTLS use
libgcrypt for cipher/digest/pk. The problem raise from our ODBC driver.
ODBC drivers are loaded dinamycally by Driver Manager (ie iODBC or
unixODBC) and unloaded as needed. So at the end you have something like
this:

  executable program => unixODBC => FreeTDS driver => GnuTLS =>
libgcrypt

every time that program open a connection to mssql unixODBC can unload
FreeTDS driver so it unload also GnuTLS and libgcrypt. Not handling DSO
finalization all one time allocations became leaks for us.

Regards, 
  Frediano Ziglio (aka freddy77)