Update zsys.c

Add missing close
Update zfile.c

Fix missing free
Update zsys.c

Add missing free
Merge pull request #769 from wysman/patch-2

Update zfile.c
Merge pull request #770 from wysman/patch-3

Update zsys.c
Merge pull request #768 from wysman/patch-1

Fix #766
Correct gsl to generate Makemodule.am instead of Makefile.am.supplement.  Move src/Makefile.am to src/Makefile
Restore 'doc' to recursive make, matching libzmq.