[4242] Addressed comments

configure.ac

@@ -152,7 +152,6 @@ AC_DEFUN([KEA_CXX_TRY_FLAG], [
 ])
 
 CXX_VERSION="unknown"
-CPPP="$CPP"
 
 # SunStudio compiler requires special compiler options for boost
 # (http://blogs.sun.com/sga/entry/boost_mini_howto)
@@ -190,6 +189,7 @@ if test "$CXX_DUMP_VERSION" \< "4.5"; then
        WARNING_GCC_44_STRICT_ALIASING_CFLAG="-fno-strict-aliasing"
 fi
 AC_SUBST(WARNING_GCC_44_STRICT_ALIASING_CFLAG)
+CPPP="$CPP"
 # gcc 5 preprocessor requires -P for checking its output
 if test "$CXX_DUMP_VERSION" \> "5"; then
        CPPP="$CPP -P"

m4macros/ax_boost_for_kea.m4

@@ -210,6 +210,7 @@ cat > conftest.cpp << EOF
 AUTOCONF_BOOST_LIB_VERSION=BOOST_LIB_VERSION
 EOF
 
+dnl CPPP is defined in configure to $CPP or $CPP -P
 BOOST_VERSION=`$CPPP $CPPFLAGS conftest.cpp | grep '^AUTOCONF_BOOST_LIB_VERSION=' | $SED -e 's/^AUTOCONF_BOOST_LIB_VERSION=//' -e 's/_/./g' -e 's/"//g' 2> /dev/null`
 if test -z "$BOOST_VERSION"; then
   BOOST_VERSION="unknown"