add `MMGEN_TRACEBACK` env var

mmgen/cfg.py

@@ -155,6 +155,7 @@ class Config(Lockable):
 	debug_subseed        = False
 	debug_tw             = False
 	devtools             = False
+	traceback            = False
 
 	# rpc:
 	rpc_host              = ''
@@ -300,6 +301,7 @@ class Config(Lockable):
 		'MMGEN_TEST_SUITE_PEXPECT',
 		'MMGEN_TEST_SUITE_POPEN_SPAWN',
 		'MMGEN_TEST_SUITE_ROOT_PFX',
+		'MMGEN_TRACEBACK',
 		'MMGEN_BLACKLIST_DAEMONS',
 		'MMGEN_BOGUS_SEND',
 		'MMGEN_BOGUS_UNSPENT_DATA',

mmgen/main.py

@@ -66,7 +66,7 @@ def launch(*, mod=None, func=None, fqmod=None, package='mmgen'):
 				e = e))
 			+ '\n' )
 
-		if os.getenv('MMGEN_EXEC_WRAPPER'):
+		if os.getenv('MMGEN_EXEC_WRAPPER') or os.getenv('MMGEN_TRACEBACK'):
 			raise
 
 		sys.exit(d.exit_val)