lit.cfg: fix a bug in simulator target

Author: Joe Shajrawi

test/lit.cfg

@@ -642,6 +642,8 @@ def use_interpreter_for_simple_runs():
 
 target_specific_module_triple = config.variant_triple
 
+config.target_run = ""
+
 if run_vendor == 'apple':
     target_specific_module_triple = '{}-apple-{}'.format(
         { 'aarch64': 'arm64', 'amd64': 'x86_64' }.get(run_cpu, run_cpu),
@@ -1356,7 +1358,8 @@ if not kIsWindows:
 			"/usr/bin/env "
 			"DYLD_LIBRARY_PATH='{0}' " # Apple option
 			"LD_LIBRARY_PATH='{0}' " # Linux option
-			.format(target_stdlib_path))
+			"SIMCTL_CHILD_DYLD_LIBRARY_PATH='{0}' " # Simulator option
+			.format(target_stdlib_path)) + config.target_run
 	else:
 		os_stdlib_path = ''
 		if run_vendor == 'apple':
@@ -1368,7 +1371,8 @@ if not kIsWindows:
 			"/usr/bin/env "
 			"DYLD_LIBRARY_PATH='{0}' " # Apple option
 			"LD_LIBRARY_PATH='{0}' " # Linux option
-			.format(all_stdlib_path))
+			"SIMCTL_CHILD_DYLD_LIBRARY_PATH='{0}' " # Simulator option
+			.format(all_stdlib_path)) + config.target_run
 
 #
 # When changing substitutions, update docs/Testing.rst.