--- SConstruct.orig	2015-04-21 17:46:54 UTC
+++ SConstruct
@@ -534,6 +534,9 @@ Export('MakeAction')
 main['LTO_CCFLAGS'] = []
 main['LTO_LDFLAGS'] = []
 
+# Add pthread
+main.Append(LIBS=['pthread'])
+
 # According to the readme, tcmalloc works best if the compiler doesn't
 # assume that we're using the builtin malloc and friends. These flags
 # are compiler-specific, so we need to set them after we detect which