Attached is a patch containing a few obvious fixes for warnings in the plugins, mostly adding consts, gpointer casts and unsigned int loop counters.
The only one that is likely to have been bad (tm) is in treebrowser.c it g_freed a static string. Setting the string const found that.
treebrowser.c still has warnings about two unused variables, since in each case some work is done to set them, the treebrowser maintainer should look and see if they are meant to be used somewhere, or remove them and the setting code.
Cheers Lex