diff --git a/src/libcmd/local.mk b/src/libcmd/local.mk
index ab0e0e43d..431d8ec06 100644
--- a/src/libcmd/local.mk
+++ b/src/libcmd/local.mk
@@ -8,7 +8,7 @@ libcmd_SOURCES := $(wildcard $(d)/*.cc)
 
 libcmd_CXXFLAGS += -I src/libutil -I src/libstore -I src/libexpr -I src/libmain -I src/libfetchers
 
-libcmd_LDFLAGS = -llowdown
+libcmd_LDFLAGS = -llowdown -pthread
 
 libcmd_LIBS = libstore libutil libexpr libmain libfetchers
 
diff --git a/src/libexpr/local.mk b/src/libexpr/local.mk
index 1aed8e152..17b83aafd 100644
--- a/src/libexpr/local.mk
+++ b/src/libexpr/local.mk
@@ -15,7 +15,7 @@ libexpr_CXXFLAGS += -I src/libutil -I src/libstore -I src/libfetchers -I src/lib
 
 libexpr_LIBS = libutil libstore libfetchers
 
-libexpr_LDFLAGS = -lboost_context
+libexpr_LDFLAGS = -lboost_context -pthread
 ifdef HOST_LINUX
  libexpr_LDFLAGS += -ldl
 endif
diff --git a/src/libfetchers/local.mk b/src/libfetchers/local.mk
index cfd705e22..bbef03afe 100644
--- a/src/libfetchers/local.mk
+++ b/src/libfetchers/local.mk
@@ -8,4 +8,6 @@ libfetchers_SOURCES := $(wildcard $(d)/*.cc)
 
 libfetchers_CXXFLAGS += -I src/libutil -I src/libstore
 
+libfetchers_LDFLAGS = -pthread
+
 libfetchers_LIBS = libutil libstore