From: Hans Petter Jansson <hpj@copyleft.no>
      Wolfgang Rosenauer <wr@rosenauer.org>
Subject: use libnsssharedhelper if available at compile time
         (can be disabled by exporting MOZ_XRE_NO_NSSHELPER=1)
References:

diff --git a/mail/app/Makefile.in b/mail/app/Makefile.in
--- a/mail/app/Makefile.in
+++ b/mail/app/Makefile.in
@@ -54,16 +54,17 @@ LOCAL_INCLUDES += \
   -I$(MOZILLA_SRCDIR)/xpcom/build \
   $(NULL)
 
 DEFINES += -DXPCOM_GLUE
 STL_FLAGS=
 
 LIBS += \
 	$(XPCOM_STANDALONE_GLUE_LDOPTS) \
+	$(NSSHELPER_LIBS) \
 	$(NULL)
 
 ifdef MOZ_LINKER
 LIBS += $(MOZ_ZLIB_LIBS)
 endif
 
 ifndef MOZ_WINCONSOLE
 ifdef MOZ_DEBUG