Replace all random functions with isc_random, isc_random_buf and isc_random_uniform API.

The three functions has been modeled after the arc4random family of
functions, and they will always return random bytes.

The isc_random family of functions internally use these CSPRNG (if available):

1. getrandom() libc call (might be available on Linux and Solaris)
2. SYS_getrandom syscall (might be available on Linux, detected at runtime)
3. arc4random(), arc4random_buf() and arc4random_uniform() (available on BSDs and Mac OS X)
4. crypto library function:
4a. RAND_bytes in case OpenSSL
4b. pkcs_C_GenerateRandom() in case PKCS#11 library

lib/dns/tests/Makefile.in

@@ -40,7 +40,6 @@ SRCS =		acl_test.c \
 		dnstap_test.c \
 		dst_test.c \
 		dnstest.c \
-		dstrandom_test.c \
 		geoip_test.c \
 		gost_test.c \
 		keytable_test.c \
@@ -73,7 +72,6 @@ TARGETS =	acl_test@EXEEXT@ \
 		dispatch_test@EXEEXT@ \
 		dnstap_test@EXEEXT@ \
 		dst_test@EXEEXT@ \
-		dstrandom_test@EXEEXT@ \
 		geoip_test@EXEEXT@ \
 		gost_test@EXEEXT@ \
 		keytable_test@EXEEXT@ \
@@ -258,11 +256,6 @@ zt_test@EXEEXT@: zt_test.@O@ dnstest.@O@ \
 			zt_test.@O@ dnstest.@O@ ${DNSLIBS} \
 				${ISCLIBS} ${LIBS}
 
-dstrandom_test@EXEEXT@: dstrandom_test.@O@ ${ISCDEPLIBS} ${DNSDEPLIBS}
-	${LIBTOOL_MODE_LINK} ${PURIFY} ${CC} ${CFLAGS} ${LDFLAGS} -o $@ \
-			dstrandom_test.@O@ ${DNSLIBS} \
-			${ISCLIBS} ${ISCPK11LIBS} ${LIBS}
-
 unit::
 	sh ${top_builddir}/unit/unittest.sh