diff --git a/mozilla/config/Linux.mk b/mozilla/config/Linux.mk
index c1427a6d82f..4b29698eec4 100644
--- a/mozilla/config/Linux.mk
+++ b/mozilla/config/Linux.mk
@@ -97,6 +97,7 @@ PORT_FLAGS		+= -DNO_INT64_T
 PLATFORM_FLAGS		+= -DLINUX2_0
 BUILD_UNIX_PLUGINS	= 1
 MKSHLIB			= $(CC) -shared -Wl,-soname -Wl,$(@:$(OBJDIR)/%.so=%.so)
+DSO_BIND_REFERENCES	= -Wl,-Bsymbolic
 ifdef BUILD_OPT
 OPTIMIZER		= -O2
 endif
diff --git a/mozilla/config/SunOS5.mk b/mozilla/config/SunOS5.mk
index d29a54736d7..a83b4c03dd9 100644
--- a/mozilla/config/SunOS5.mk
+++ b/mozilla/config/SunOS5.mk
@@ -172,6 +172,7 @@ MUST_BOOTLEG_ALLOCA	= 1
 BUILD_UNIX_PLUGINS	= 1
 
 MKSHLIB			= $(LD) $(DSO_LDOPTS)
+DSO_BIND_REFERENCES	= -Bsymbolic
 
 DSO_LDOPTS		= -G -L$(MOTIF)/lib -L/usr/openwin/lib
 DSO_LDFLAGS		=