Add -ldl to compile rules which requires HDF5 lib.
   bug 18909

[git-p4: depot-paths = "//depot/software/assembly/cpp/": change = 128048]
   Add -L(...) to compile rules for samtom4 and samtoh5, so that if libz 
   is not installed, gcc will try to use the prebuilt libz shared library.
   bug 18909

[git-p4: depot-paths = "//depot/software/assembly/cpp/": change = 128053]