Added missing pthread gpr requirement
diff --git a/templates/Makefile.template b/templates/Makefile.template
index 6b4b3e1..2a2f696 100644
--- a/templates/Makefile.template
+++ b/templates/Makefile.template
@@ -363,12 +363,11 @@
 # gpr .pc file
 PC_NAME = Google Public Runtime
 PC_DESCRIPTION = Google Public Runtime
-PC_CFLAGS =
+PC_CFLAGS = -pthread
 PC_REQUIRES_PRIVATE =
+PC_LIBS_PRIVATE = -lpthread
 ifeq ($(SYSTEM),Darwin)
-PC_LIBS_PRIVATE = -lrt
-else
-PC_LIBS_PRIVATE =
+PC_LIBS_PRIVATE += -lrt
 endif
 GPR_PC_FILE := $(PC_TEMPLATE)