[source] busybox: add missing TARGET_CPPFLAGS and TARGET_LDFLAGS

[LEDE Commits]

neoraider pushed a commit to source.git, branch master:
https://git.lede-project.org/20c349f68ca108d8b20363efbf5fa698e8446009

commit 20c349f68ca108d8b20363efbf5fa698e8446009
Author: Matthias Schiffer <mschiffer at universe-factory.net>
AuthorDate: Sun Dec 10 18:04:53 2017 +0100

    busybox: add missing TARGET_CPPFLAGS and TARGET_LDFLAGS
    
    Unconditionally pass TARGET_CPPFLAGS (not passed at all before) and
    TARGET_LDFLAGS (passed only in certain non-default configuration before the
    Makefile streamlining). Without these flags, hardening options
    (PKG_FORTIFY_SOURCE and PKG_RELRO) were not actually applied to busybox.
    
    The addition of these flags increases the size of the stripped busybox
    binary by about 6KB (~4KB with fortify headers, ~2KB with "-znow -zrelro")
    with the default hardening options PKG_FORTIFY_SOURCE_1 and PKG_RELRO_FULL.
    
    Signed-off-by: Matthias Schiffer <mschiffer at universe-factory.net>
---
 package/utils/busybox/Makefile | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/package/utils/busybox/Makefile b/package/utils/busybox/Makefile
index 54ad986..8866756 100644
--- a/package/utils/busybox/Makefile
+++ b/package/utils/busybox/Makefile
@@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=busybox
 PKG_VERSION:=1.27.2
-PKG_RELEASE:=2
+PKG_RELEASE:=3
 PKG_FLAGS:=essential
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.bz2
@@ -83,7 +83,8 @@ endif
 
 MAKE_VARS :=
 MAKE_FLAGS += \
-	EXTRA_CFLAGS="$(TARGET_CFLAGS)" \
+	EXTRA_CFLAGS="$(TARGET_CFLAGS) $(TARGET_CPPFLAGS)" \
+	EXTRA_LDFLAGS="$(TARGET_LDFLAGS)" \
 	LDLIBS="$(LDLIBS)" \
 	SKIP_STRIP=y
 ifneq ($(findstring c,$(OPENWRT_VERBOSE)),)