BUILD: ssl: Fix build with OpenSSL without NPN capability

OpenSSL can be built without NEXTPROTONEG support by passing
-no-npn to the configure script. This sets the
OPENSSL_NO_NEXTPROTONEG flag in opensslconf.h

Since NEXTPROTONEG is now considered deprecated, it is superseeded
by ALPN (Application Layer Protocol Next), HAProxy should allow
building withough NPN support.
1 file changed