[source] openvpn: reduce binary size using --gc-sections on linking

[LEDE Commits]

nbd pushed a commit to source.git, branch master:
https://git.lede-project.org/2bc747aaead96d3eebc97a9d6c638b8eb44de180

commit 2bc747aaead96d3eebc97a9d6c638b8eb44de180
Author: Felix Fietkau <nbd at nbd.name>
AuthorDate: Sat Dec 10 12:39:54 2016 +0100

    openvpn: reduce binary size using --gc-sections on linking
    
    Saves around 9kb gzipped on MIPS
    
    Signed-off-by: Felix Fietkau <nbd at nbd.name>
---
 package/network/services/openvpn/Makefile | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/package/network/services/openvpn/Makefile b/package/network/services/openvpn/Makefile
index 11b6aab..24fb897 100644
--- a/package/network/services/openvpn/Makefile
+++ b/package/network/services/openvpn/Makefile
@@ -65,6 +65,9 @@ CONFIGURE_VARS += \
 	IPROUTE=/sbin/ip \
 	NETSTAT=/sbin/netstat
 
+TARGET_CFLAGS += -ffunction-sections -fdata-sections
+TARGET_LDFLAGS += -Wl,--gc-sections
+
 define Build/Configure
 	$(call Build/Configure/Default, \
 		$(if $(CONFIG_OPENVPN_$(BUILD_VARIANT)_ENABLE_SMALL),--enable-small) \