Ensure that CFLAGS and/or LDFLAGS provided to configure script are preserved.

Cross-compilation environments want to provide 'defaults' for compiler and
linker options, and frequently do this by specifying CFLAGS and LDFLAGS in the
environment or as command-line arguments to the configure script. This patch
modifies the configure script and Makefile to preserve these settings and
ensure they are used in the build process.



git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@214696 65c4cc65-6c06-0410-ace0-fbb531ad65f3