Update required and optional package names and presence tests.

git-svn-id: https://hamlib.svn.sourceforge.net/svnroot/hamlib/trunk@3015 7ae35d74-ebe9-4afe-98af-79ac388436b8

README.developer

@@ -159,26 +159,26 @@ version or you won't even be able to build from the SVN checkout.
 * autoconf      2.54                        # autoconf --version
 * automake      1.7                         # automake --version
 * libtool       2.2.6b                      # libtool --version
-* libltdl-dev   2.2.6b                      # (Debian package for new libtool)
 * svn for connection to hamlib.svn.sourceforge.net
 
 N.B. Hamlib no longer supports versions of libtool earlier than 2.2.6b in
-compliance with CVE-2009-3736.
+compliance with CVE-2009-3736.  If an older version is found, Hamlib will use
+the bundled libtool 2.2.6b instead.
 
-Optional:
+Optional, but highly recommended:
 * GNU C++                           # g++ --version
 * swig (for bindings)   1.3.14      # swig -version
 * perl devel                        # h2xs
-* tcl devel
-* python devel
+* tcl devel                         # tcltk-depends
+* python devel                      # python-config
 * libxml2 devel                     # xml2-config --version
-* libgd devel
-* libusb devel
+* libgd2 devel                      # gdlib-config --version
+* libusb devel                      # libusb-config --version (not 1.0.0!)
 * RPC devel (libc-dev)              # rpcgen --version
 
 Documentation:
-* doxygen
-* DocBook
+* Doxygen
+* DocBook                           # Deprecated in favor of Doxygen
 
 Note:  Some systems can have several versions of the autotools installed.
 In that case, autoconf may be called "autoconf2.50", autoheader