Do some liburcu_* magic to fix builds on *BSD and Mac OS X

src/Makefile.am

@@ -321,10 +321,11 @@ libknotd_la_SOURCES =				\
 
 libknotd_la_CPPFLAGS  = $(AM_CPPFLAGS) $(systemd_CFLAGS) $(liburcu_CFLAGS)
 libknotd_la_LDFLAGS = $(AM_LDFLAGS) $(systemd_LIBS) $(liburcu_LIBS)
-libknotd_la_LIBADD = libknot.la
+libknotd_la_LIBADD = libknot.la $(liburcu_LIBS)
 
+knotd_CPPFLAGS = $(liburcu_CFLAGS)
 knotd_LDADD = libknotd.la
-knotc_LDADD = libknotd.la libknot.la 
+knotc_LDADD = libknotd.la libknot.la
 knot1to2_LDADD = libknot.la
 
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