The $PATH variable is only for paths that contain executables not libraries. For this create a text file in /etc/ld.so.conf.d/ that contains the path in which the libs are. The file has to end with
.conf/opt/wx/2.6/lib
Then run ldconfig as root and it will find the libs
But one question: Why don't you use the wxGTK package that's shipped with suse ? You wouldn't have any problem (at least not this one) when using it.
Only selfcompile software if it's not available as package for your distri. Everything else can result in an unstable system :!: