[3049] Check for offset_ptr with -Werror

configure.ac

@@ -883,7 +883,7 @@ LIBS=$LIBS_SAVED
 AX_BOOST_FOR_BIND10
 # Boost offset_ptr is required in one library and not optional right now, so
 # we unconditionally fail here if it doesn't work.
-if test "$BOOST_OFFSET_PTR_WOULDFAIL" = "yes"; then
+if test "$BOOST_OFFSET_PTR_WOULDFAIL" = "yes" -a "$werror_ok" = 1; then
     AC_MSG_ERROR([Failed to compile a required header file.  Try upgrading Boost to 1.44 or higher (when using clang++) or specifying --without-werror.  See the ChangeLog entry for Trac no. 2147 for more details.])
 fi
 

m4macros/ax_boost_for_bind10.m4

@@ -86,6 +86,8 @@ AC_TRY_COMPILE([
 
 # Boost offset_ptr is known to not compile on some platforms, depending on
 # boost version, its local configuration, and compiler.  Detect it.
+CXXFLAGS_SAVED="$CXXFLAGS"
+CXXFLAGS="$CXXFLAGS -Werror"
 AC_MSG_CHECKING([Boost offset_ptr compiles])
 AC_TRY_COMPILE([
 #include <boost/interprocess/offset_ptr.hpp>
@@ -94,6 +96,7 @@ AC_TRY_COMPILE([
  BOOST_OFFSET_PTR_WOULDFAIL=no],
 [AC_MSG_RESULT(no)
  BOOST_OFFSET_PTR_WOULDFAIL=yes])
+CXXFLAGS="$CXXFLAGS_SAVED"
 
 # Detect build failure case known to happen with Boost installed via
 # FreeBSD ports