Expand variables using autoconf. Add and use COMPILE variable. Add VPATH support to build outside source dir. Rename CDEFS to DEFS.
Expand variables using autoconf.
Add and use COMPILE variable.
Add VPATH support to build outside source dir.
Rename CDEFS to DEFS.

ksophocleous/libsrtp,Distrotech/libsrtp,Distrotech/libsrtp,persmule/libsrtp,ksophocleous/libsrtp,yarrcc/libsrtp-ios,yarrcc/libsrtp-ios,persmule/libsrtp,persmule/libsrtp,cuijinquan/libsrtp,cuijinquan/libsrtp,cuijinquan/libsrtp,yarrcc/libsrtp-ios