--- file_not_specified_in_diff	
+++ file_not_specified_in_diff	
@@ -, +, @@ 
--- 1/m4/boost.m4
+++ 2/m4/boost.m4
@@ -72,7 +72,9 @@ 
 dnl everything else.
 dnl Cannot use 'dnl' after [$4] because a trailing dnl may break AC_CACHE_CHECK
 (eval "$ac_cpp conftest.$ac_ext") 2>&AS_MESSAGE_LOG_FD |
+  grep -v '#' |
   tr -d '\r' |
+  tr -s '\n' ' ' |
   $SED -n -e "$1" >conftest.i 2>&1],
   [$3],
   [$4])
@@ -206,7 +208,7 @@ 
   AC_CACHE_CHECK([for Boost's header version],
     [boost_cv_lib_version],
     [m4_pattern_allow([^BOOST_LIB_VERSION$])dnl
-     _BOOST_SED_CPP([/^boost-lib-version = /{s///;s/\"//g;p;q;}],
+     _BOOST_SED_CPP([[/^boost-lib-version = /{s///;s/[\" ]//g;p;q;}]],
                     [#include <boost/version.hpp>
 boost-lib-version = BOOST_LIB_VERSION],
     [boost_cv_lib_version=`cat conftest.i`])])