[trac622] Update documentation

Remove (most) references to log4cxx in the documentation.  Ensure
that the documentation and the "experimental" files mentioned in it
are included in the distribution.

src/lib/log/Makefile.am

@@ -23,6 +23,10 @@ liblog_la_SOURCES += message_types.h
 liblog_la_SOURCES += root_logger_name.cc root_logger_name.h
 liblog_la_SOURCES += strutil.h strutil.cc
 
+EXTRA_DIST   = README
+EXTRA_DIST  += logger_impl_log4cxx.cc logger_impl_log4cxx.h
+EXTRA_DIST  += xdebuglevel.cc xdebuglevel.h
+
 # Note: the ordering matters: -Wno-... must follow -Wextra (defined in
 # B10_CXXFLAGS)
 liblog_la_CXXFLAGS = $(AM_CXXFLAGS)

src/lib/log/documentation.txt

@@ -233,8 +233,8 @@ To use the current version of the logging:
 
        isc::log::Logger logger("myname", true);
 
-   The argument is ignored for underlying implementations other than log4cxx.
-   See below for the use of this argument.
+   (The argument is required to support a possible future implementation of
+   logging.  Currently it has no effect.)
 
 3. The main program unit should include a call to isc::log::runTimeInit()
    (defined in logger_support.h) to set the logging severity, debug log level,
@@ -379,56 +379,9 @@ Outstanding Issues
 
 log4cxx Issues
 ==============
+Some experimental code to utilise log4cxx as an underlying implementation
+is present in the source code directory, although it is not currently used.
+The files are:
 
-Second Argument in Logger Constructor
--------------------------------------
-As noted above, when using log4cxx as the underlying implementation, the
-argument to the logger's constructor should be set true if declaring the
-logger within a method and set false (or omitted) if declaring the logger
-external to an execution unit.
-
-This is due to an apparent bug in the underlying log4cxx, where the deletion
-of a statically-declared object at program termination can cause a segment
-fault. (The destruction of internal memory structures can sometimes happen
-out of order.)  By default the Logger class creates the structures in
-its constructor but does not delete them in the destruction.  The default
-behavious works because instead of reclaiming memory at program run-down,
-the operating system reclaims it when the process is deleted.
-
-Setting the second argument "true" causes the Logger's destructor to delete
-the log4cxx structures.  This does not cause a problem if the program is
-not terminating.  So use the second form when declaring an automatic instance
-of isc::log::Logger on the stack.
-
-Building with log4cxx
----------------------
-Owing to issues with versions of log4cxx on different systems, log4cxx was
-temporarily disabled.  To use log4cxx on your system:
-
-* Uncomment the log4cxx lines in configure.ac
-* In src/lib/log, replace the logger_impl.{cc,h} files with their log4cxx
-  equivalents, i.e.
-
-  cp logger_impl_log4cxx.h logger_impl.h
-  cp logger_impl_log4cxx.cc logger_impl.cc
-
-* In src/lib/log/Makefile.am, uncomment the lines:
-
-  # AM_CPPFLAGS += $(LOG4CXX_INCLUDES)
-
-  # liblog_la_SOURCES += xdebuglevel.cc xdebuglevel.h
-
-  # liblog_la_LDFLAGS = $(LOG4CXX_LDFLAGS)
-
-* In src/lib/log/test, re-enable testing of the log4cxx implementation
-  class, i.e.
-
-  cp logger_impl_log4cxx_unittest.cc logger_impl_unittest.cc
-
-  ... and uncomment the following lines in Makefile.am:
-
-  # run_unittests_SOURCES += logger_impl_unittest.cc
-
-  # run_unittests_SOURCES += xdebuglevel_unittest.cc
-
-Then rebuild the system from scratch.
+   logger_impl_log4cxx.{cc,h}
+   xdebuglevel.{cc,h}