Build was overriding openwrt pcap include directory.

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

Signed-off-by: W. Michael Petullo <mike@flyn.org>

The configure script incorrectly mangles `CFLAGS` by attempting to remove
`-Werror` from it, thus turning `-Werror=format-security` into just
`=format-security` which will cause subsequent autoconf tests to fail.

Patch out the custom `CFLAGS` mangling to fix the build.

Signed-off-by: Jo-Philipp Wich <jow@openwrt.org>

Signed-off-by: Luka Perkov <luka@openwrt.org>