add a few comments for clarification
trace.h whitespace cleanup
trace.c whitespace cleanup
kill IF_TRACING_DO and related macros
use uintptr_t for node ID of context stack and accessors
kill IF_TRACING
remove unused/rarely used macros
remove print_error_msg-related private macros from public header
remove unused nonfatal_err_cnt
namespacing of binary trace tag macros