If you're using wxWidgets version >= 2.5.0, please be sure of the following:
1) If you're going to compile any of the GUI applications (amule, amulecmdDLG, amulewebDLG, wxcas), do not install wxBase. Install only wxGTK. If you had already installed wxBase also (after wxGTK), you can still compile aMule, but it gets more complicated: do:
wx_config_args="--toolkit=gtk" ./configure
This should do the trick.
2) If you want to only compile command-line applications (amuled, amulecmd, amuleweb, cas), it doesn't matter which wx you install wxBase or wxGTK. Any of the two will fit. That's because in wxWidgets releases >= 2.5.0 wxGTK contains the Base library too.