optimized function calls a few percent (especially recursive function calls)

Rev: src/docode.c:1.129
Rev: src/interpret.c:1.240
Rev: src/interpret.h:1.96
Rev: src/object.c:1.180
Rev: src/object.h:1.64
Rev: src/svalue.c:1.116
Rev: src/svalue.h:1.95