lazy use of NULL pointers causes segfaults on Solaris
On Solaris, NULL pointers are not translated when used with printf; they cause segfaults. On Linux, %s results in "(null)". See also "Dealing with NULL Pointers" at http://developers.sun.com/solaris/articles/portingUNIXapps.html. Current workaround is to LD_PRELOAD=/usr/lib/0@0.so.1 on Solaris.
One such place this can be fixed is in src/misc/messages.c, in the msg_StackMsg function. Above the return statement, check to see if p_ctx->psz_message is null, and if it is return "" instead. This particular instance was found when an invalid or unavailable URL was attempted in VLC. In addition, loading a playlist that has unreachable URLs results in a segfault, but I have not backtraced that one to a specific fix.
Marked difficulty hard since it probably involves extensive code review.