Integrate QUIC/TLS interaction interface into the build system

This commit integrates the QUIC/TLS interaction interface into the
projects build system.

configure.ac

@@ -649,6 +649,7 @@ LIBS="$OPENSSL_LIBS $LIBS"
 #
 # Check for functions added in OpenSSL or LibreSSL
 #
+AC_CHECK_FUNCS([CRYPTO_free_ex_index])
 AC_MSG_CHECKING([for Ed448 support])
 AC_COMPILE_IFELSE(
     [AC_LANG_PROGRAM([[#include <openssl/evp.h>]],

lib/isc/Makefile.am

@@ -256,6 +256,18 @@ libisc_la_LIBADD +=		\
 	$(LIBXML2_LIBS)
 endif HAVE_LIBXML2
 
+if HAVE_LIBNGTCP2
+libisc_la_SOURCES +=		\
+	quic/quic-int.h	\
+	quic/tls_quic.c
+
+libisc_la_CPPFLAGS +=		\
+	$(LIBNGTCP2_CFLAGS)
+
+libisc_la_LIBADD +=		\
+	$(LIBNGTCP2_LIBS)
+endif
+
 if !HAVE_SYSTEMTAP
 DTRACE_DEPS = libisc_la-rwlock.lo libisc_la-job.lo
 DTRACE_OBJS = .libs/libisc_la-rwlock.$(OBJEXT) .libs/libisc_la-job.$(OBJEXT)