Why --enable-compat24 is used? Does any depending application need it? BTW, if you decide not to use it, you'll need to recompile all applications, otherwise you'll get: $ codeblocks Fatal Error: Mismatch between the program and library build versions detected. The library used 2.8 (no debug,Unicode,compiler with C++ ABI 1002,wx containers,compatible with 2.6), and your program used 2.8 (no debug,Unicode,compiler with C++ ABI 1002,wx containers,compatible with 2.4,compatible with 2.6). Aborted
Is there a downside of enabling it? I can turn it off, but it seemed good to have.
wx by default enables compatibility with one past version only (2.6 in this case), and imho it's enough. When applications are ported to a higher wx version, they usually are made to work with wx compiled with default settings (by just running ./configure), so enabling more compatibility is useless and only makes library bigger (unless there are apps which do not work without --enable-compat24, but I don't know any). Anyway, it's a minor issue.
I think retaining compatibility for two versions is valuable enough that I'm inclined to keep it on. How much space/memory is saved by not enabling it?