Avoid spurious compilation failures in liburcu headers

When liburcu is not installed from a system package, its headers are
not treated as system headers by the compiler, so BIND's -Werror and
other warning options take effect. The liburcu headers have a lot
of inline functions, some of which do not use all their arguments,
which BIND's build treats as an error.

lib/isc/include/isc/urcu.h

@@ -15,6 +15,10 @@
 
 #include <isc/util.h>
 
+/* when urcu is not installed in a system header location */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wunused-parameter"
+
 /* Inline small (less than 10 lines) functions */
 #define URCU_INLINE_SMALL_FUNCTIONS
 
@@ -30,6 +34,8 @@
 #include <urcu/rculfhash.h>
 #include <urcu/rculist.h>
 
+#pragma GCC diagnostic pop
+
 #if defined(RCU_QSBR)
 
 /*

tests/bench/Makefile.am

@@ -4,6 +4,7 @@ AM_CFLAGS += -Wno-vla
 
 AM_CPPFLAGS +=				\
 	$(LIBUV_CFLAGS)			\
+	$(LIBURCU_CFLAGS)		\
 	$(LIBISC_CFLAGS)		\
 	$(LIBDNS_CFLAGS)		\
 	-I$(top_srcdir)/fuzz		\
@@ -13,6 +14,7 @@ AM_CPPFLAGS +=				\
 
 LDADD +=				\
 	$(LIBUV_LIBS)			\
+	$(LIBURCU_LIBS)			\
 	$(LIBISC_LIBS)			\
 	$(LIBDNS_LIBS)			\
 	$(top_builddir)/tests/libtest/libtest.la

tests/dns/Makefile.am

@@ -4,6 +4,7 @@ AM_CPPFLAGS +=				\
 	$(LIBISC_CFLAGS)		\
 	$(LIBDNS_CFLAGS)		\
 	$(LIBUV_CFLAGS)			\
+	$(LIBURCU_CFLAGS)		\
 	$(KRB5_CFLAGS)			\
 	-DSRCDIR=\"$(abs_srcdir)\"	\
 	-DBUILDDIR=\"$(abs_builddir)\"	\
@@ -13,6 +14,7 @@ AM_CPPFLAGS +=				\
 LDADD +=				\
 	$(LIBISC_LIBS)			\
 	$(LIBUV_LIBS)			\
+	$(LIBURCU_LIBS)			\
 	$(LIBDNS_LIBS)
 
 check_PROGRAMS =		\

tests/isc/Makefile.am

@@ -2,11 +2,13 @@ include $(top_srcdir)/Makefile.top
 
 AM_CPPFLAGS +=			\
 	$(LIBISC_CFLAGS)	\
+	$(LIBURCU_CFLAGS)	\
 	$(LIBUV_CFLAGS)		\
 	-I$(top_srcdir)/lib/isc
 
 LDADD +=			\
 	$(LIBISC_LIBS)		\
+	$(LIBURCU_LIBS)		\
 	$(LIBUV_LIBS)
 
 check_PROGRAMS =	\