diff --git a/src/runtime/c/Makefile.am b/src/runtime/c/Makefile.am
index 4942b8aa4..918c5b48f 100644
--- a/src/runtime/c/Makefile.am
+++ b/src/runtime/c/Makefile.am
@@ -27,7 +27,7 @@ libpgf_la_SOURCES = \
 	pgf/expr.h \
 	pgf/namespace.h
 
-libpgf_la_LDFLAGS = "-no-undefined"
+libpgf_la_LDFLAGS = "-no-undefined -lrt"
 libpgf_la_CXXFLAGS = -fno-rtti
 
 bin_PROGRAMS =