Despite what ./configure --help says: --enable-tracing enable verbose tracing code tracing is actually enabled by default (run "grep -r PLY_ENABLE_TRACING" after running ./configure). I suggest splitting that option into USE=debug. In addition, src/client/plymouth.c explicitly searches for "plymouth:debug", although src/main.c says: /* we now use plymouth.argument for kernel commandline arguments. * It used to be plymouth:argument. This bit just rewrites all : to be . */
Fixed as suggested. No revbump, because -N to emerge should handle this.