diff --git a/SConstruct b/SConstruct
index b29e777..e1eec23 100644
--- a/SConstruct
+++ b/SConstruct
@@ -54,8 +54,8 @@ env = Environment(tools = ['default', 'textfile'])
 env.AddMethod(InstallPerm)
 Export('env', 'build_type', 'prefix', 'version_info', 'test_xml')
 
-env.Append(CFLAGS = ['-Wall', '-Wextra', '-pipe', '-ggdb'])
-env.Append(LINKFLAGS = ['-O2'])
+env.Append(CFLAGS = ['-Wall', '-Wextra', '-pipe', '-ggdb', '-pthread'])
+env.Append(LINKFLAGS = ['-O2', '-pthread'])
 env.Append(CPPDEFINES = ['_FILE_OFFSET_BITS=64'])
 
 if build_type == 'release':
diff --git a/src/SConscript b/src/SConscript
index c28fcde..d5dff4d 100644
--- a/src/SConscript
+++ b/src/SConscript
@@ -6,7 +6,6 @@ ucore_env = env.Clone()
 #substitute @version_xx@ strings
 subst_version_info = dict(('@' + key + '@', version_info[key]) for key in version_info)
 ucore_env.Substfile('ucore_version.c.in', SUBST_DICT = subst_version_info)
-ucore_env.Append(CFLAGS = ['-pthread'])
 
 sources = ucore_env.Glob('*.c')
 headers = ucore_env.Glob('*.h')