Moved compilation_depth to struct compilation. Yet another step on the way to making the compiler thread safe. Got rid of some now unused cleanup code in dynamic_load.c. Rev: src/builtin_functions.c:1.656 Rev: src/dynamic_load.c:1.91 Rev: src/encode.c:1.264 Rev: src/language.yacc:1.416 Rev: src/pike_compiler.h:1.9 Rev: src/program.c:1.679 Rev: src/program.h:1.240