configure warning caused by AC_CHECK_HEADER

[Markus Jarvinen]

Here is a simple configure.ac to produce the warning:
-------------------------------------------------------------------------
AC_INIT

AC_PROG_CXX

# data files
CXXFLAGS="-DDATADIR=\\\"$(datadir)\\\""

# boost
AC_LANG([C++])
AC_CHECK_HEADER(boost/shared_ptr.hpp)
-------------------------------------------------------------------------
Here's the output from 'autoconf && ./configure':

checking for g++... g++
checking for C++ compiler default output... a.out
checking whether the C++ compiler works... yes
checking whether we are cross compiling... no
checking for suffix of executables... 
checking for suffix of object files... o
checking whether we are using the GNU C++ compiler... yes
checking whether g++ accepts -g... yes
./configure: line 1: datadir: command not found
checking how to run the C++ preprocessor... g++ -E
checking for egrep... grep -E
checking for ANSI C header files... no
checking for sys/types.h... no
checking for sys/stat.h... no
checking for stdlib.h... no
checking for string.h... no
checking for memory.h... no
checking for strings.h... no
checking for inttypes.h... no
checking for stdint.h... no
checking for unistd.h... no
checking boost/shared_ptr.hpp usability... no
checking boost/shared_ptr.hpp presence... yes
configure: WARNING: boost/shared_ptr.hpp: present but cannot be compiled
configure: WARNING: boost/shared_ptr.hpp: check for missing prerequisite
headers?
configure: WARNING: boost/shared_ptr.hpp: proceeding with the
preprocessor's result
configure: WARNING:     ## ------------------------------------ ##
configure: WARNING:     ## Report this to address@hidden ##
configure: WARNING:     ## ------------------------------------ ##
checking for boost/shared_ptr.hpp... yes

I don't get any warnings if I remove the CXXFLAGS line from configure.ac .

-- 
Markus Järvinen
address@hidden
http://personal.inet.fi/koti/mj/