busybox: compile with debug information

The added debug information is stripped of during packaging, so it does not
increase the package size. It does however slightly change offsets in the
code, preventing the weird ash segfaults we've been seeing. Also, if the
issue returns, we'll have debug information matching the coredumps.

patches/lede/0034-busybox-compile-with-debug-information.patch

+From: Matthias Schiffer <mschiffer@universe-factory.net>
+Date: Mon, 3 Jul 2017 01:40:32 +0200
+Subject: busybox: compile with debug information
+
+The added debug information is stripped of during packaging, so it does not
+increase the package size. It does however slightly change offsets in the
+code, preventing the weird ash segfaults we've been seeing. Also, if the
+issue returns, we'll have debug information matching the coredumps.
+
+diff --git a/package/utils/busybox/Makefile b/package/utils/busybox/Makefile
+index 40bddd6b58195828951d1e48c12848f4fbfc1430..bba1a40568d4bd0543e4768439a249c89779f29a 100644
+--- a/package/utils/busybox/Makefile
++++ b/package/utils/busybox/Makefile
+@@ -91,6 +91,8 @@ ifdef CONFIG_BUSYBOX_DEFAULT_NSLOOKUP_LEDE
+   endif
+ endif
+ 
++TARGET_CFLAGS += -g
++
+ define Build/Compile
+ 	+$(MAKE) $(PKG_JOBS) -C $(PKG_BUILD_DIR) \
+ 		CC="$(TARGET_CC)" \