softethervpn: add -Wl,-rpath to HOST_LDFLAGS

Avoids failures related to the absence of a matching libreadline.so in
the host system.

Signed-off-by: Eneas U de Queiroz <cote2004-github@yahoo.com>

net/softethervpn/Makefile

@@ -39,6 +39,7 @@ HOST_MAKE_FLAGS += -C $(HOST_BUILD_DIR)
 # Select 32 or 64 bit Makefile for host build depending on host architecture
 HOST_MAKE_FLAGS += -f src/makefiles/linux_$(if $(shell uname -m | grep 64),64,32)bit.mak
 
+HOST_LDFLAGS += -Wl,-rpath="$(STAGING_DIR_HOSTPKG)/lib"
 # Prevent calling upstream configure
 define Host/Configure
 endef