[1253] Fix dependencies in Makefile

Autotools don't track dependencies on libraries with absolute path. As
the library lives in the same directory, the directory order does not
help, so we need the dep to be tracked explicitly, which means we need
to use relative path.

The old version breaks with make -j<a lot>.

src/lib/datasrc/Makefile.am

@@ -28,13 +28,13 @@ nodist_libdatasrc_la_SOURCES = datasrc_messages.h datasrc_messages.cc
 sqlite3_ds_la_SOURCES = sqlite3_accessor.h sqlite3_accessor.cc
 sqlite3_ds_la_LDFLAGS = -module
 sqlite3_ds_la_LIBADD = $(top_builddir)/src/lib/exceptions/libexceptions.la
-sqlite3_ds_la_LIBADD += $(top_builddir)/src/lib/datasrc/libdatasrc.la
+sqlite3_ds_la_LIBADD += libdatasrc.la
 sqlite3_ds_la_LIBADD += $(SQLITE_LIBS)
 
 memory_ds_la_SOURCES = memory_datasrc.h memory_datasrc.cc
 memory_ds_la_LDFLAGS = -module
 memory_ds_la_LIBADD = $(top_builddir)/src/lib/exceptions/libexceptions.la
-memory_ds_la_LIBADD += $(top_builddir)/src/lib/datasrc/libdatasrc.la
+memory_ds_la_LIBADD += libdatasrc.la
 
 libdatasrc_la_LIBADD = $(top_builddir)/src/lib/exceptions/libexceptions.la
 libdatasrc_la_LIBADD += $(top_builddir)/src/lib/dns/libdns++.la