[master] version the log library

This is to fix the ongoing problem seen on a builder:

/libexec/ld-elf.so.1: /usr/home/jreed/builder/work/BIND10-cppcheck/20120516030045-FreeBSD8-amd64-GCC/build/src/lib/datasrc/tests/.libs/run_unittests: Undefined symbol "_ZN3isc3log23checkExcessPlaceholdersEPSsj"

It was matching the library in the base system instead.

This was discussed on jabber some weeks ago.

src/lib/log/Makefile.am

@@ -47,3 +47,4 @@ liblog_la_CXXFLAGS += -Wno-error
 endif
 liblog_la_CPPFLAGS = $(AM_CPPFLAGS) $(LOG4CPLUS_INCLUDES)
 liblog_la_LIBADD   = $(LOG4CPLUS_LIBS) $(top_builddir)/src/lib/util/libutil.la
+liblog_la_LDFLAGS = -no-undefined -version-info 1:0:0