Added result type and stacktrace capabilities.

LibConf

@@ -3,6 +3,7 @@ Import('env')
 
 mijin_sources = Split("""
     source/mijin/async/coroutine.cpp
+    source/mijin/debug/stacktrace.cpp
     source/mijin/debug/symbol_info.cpp
     source/mijin/io/process.cpp
     source/mijin/io/stream.cpp
@@ -12,15 +13,18 @@ mijin_sources = Split("""
     source/mijin/virtual_filesystem/stacked.cpp
 """)
 
-env.UnityStaticLibrary(
+lib_libbacktrace = env.Cook('libbacktrace')
+
+lib_mijin = env.UnityStaticLibrary(
     target = env['LIB_DIR']  + '/mijin',
-    source = mijin_sources
+    source = mijin_sources,
+    dependencies = [lib_libbacktrace]
 )
 
 LIB_CONFIG = {
     'CPPPATH': [env.Dir('source')],
     'CPPDEFINES': [],
-    'LIBS': ['mijin']
+    'DEPENDENCIES': [lib_mijin]
 }
 
 if env['BUILD_TYPE'] == 'debug':