diff -up firefox-38.0/mozilla-beta/security/nss/coreconf/Linux.mk.old firefox-38.0/mozilla-beta/security/nss/coreconf/Linux.mk
--- firefox-38.0/mozilla-beta/security/nss/coreconf/Linux.mk.old	2015-03-30 18:54:40.000000000 -0400
+++ firefox-38.0/mozilla-beta/security/nss/coreconf/Linux.mk	2015-04-02 09:27:11.893566786 -0400
@@ -127,7 +127,7 @@ endif
 
 
 ifeq ($(USE_PTHREADS),1)
-OS_PTHREAD = -lpthread 
+OS_PTHREAD = -lpthread -lrt
 endif
 
 OS_CFLAGS		= $(DSO_CFLAGS) $(OS_REL_CFLAGS) $(ARCHFLAG) -Wall -Werror-implicit-function-declaration -Wno-switch -pipe -ffunction-sections -fdata-sections -DLINUX -Dlinux -DHAVE_STRERROR