Fixed --with-cleanup-on-exit to work without rtldebug.

Rev: src/array.h:1.64
Rev: src/dmalloc.h:1.53
Rev: src/gc.c:1.259
Rev: src/gc.h:1.116
Rev: src/main.c:1.210
Rev: src/mapping.h:1.58
Rev: src/multiset.h:1.37
Rev: src/object.h:1.87
Rev: src/pike_memory.c:1.156
Rev: src/program.h:1.210
Rev: src/stralloc.c:1.168
Rev: src/stralloc.h:1.82