Fix error caused by C warning flags propogating to C++

As some of these are not supported in C++
Additionally, trim DEBUGFLAGS down to focus optimisation level
and debug symbol level only, as --enable-werror will enable
all of the warning flags that will ever be needed

configure.ac

@@ -66,7 +66,7 @@ AC_ARG_ENABLE([debug],
     [debug=$enableval], [debug=no])
 
 if test "x${debug}" = "x${enableval}"; then
-  DEBUGCFLAGS="-Wall -Werror -Wformat -Wfatal-errors -O0 -g3"
+  DEBUGCFLAGS="-O0 -g3"
   AC_SUBST([DEBUGCFLAGS])
 fi
 

examples/Makefile.am

@@ -22,7 +22,7 @@
 # WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 AM_CFLAGS = $(WARNCFLAGS) $(DEBUGCFLAGS)
-AM_CXXFLAGS = $(WARNCFLAGS) $(DEBUGCFLAGS)
+AM_CXXFLAGS = $(DEBUGCFLAGS)
 AM_CPPFLAGS = \
 	-I$(top_srcdir)/lib/includes \
 	-I$(top_builddir)/lib/includes \