emscripten_force_exit option
remove no longer needed bad_exception hack; fixes #2560; 1.21.6
EMCC_ONLY_FORCED_STDLIBS option
Implement <sys/unistd.h> compatibility.
Update default environment variables and argv[0].
Merge pull request #2565 from sunfishcode/incoming

Incoming
update test_env
consolidate Module.thisProgram
make environ work by itself; fixes #2557
Fix IDBFS for webworkers
fix getFuncWrapper for aliased function pointers, fixes #2010
Merge pull request #2476 from amatus/push-upstream

Fix IDBFS for webworkers
give an error if IDBFS is used without IDB support
update test_fs_base
update other.test_mkdir_silly
disable test_environ in non-fastcomp
keep a list of readdir() entries during read start; fixes #2528
docs improvements
update libcxxabi symbols
run sanity checks with -v + an input file