dnl
dnl Autoconf support for finding OpenSSL
dnl
dnl XXX should allow alternative OpenSSL prefix using --with-openssl=<prefix>
dnl

AC_DEFUN(AC_CONFIG_OPENSSL, [

    if test "$ac_bsp" = yes; then
        ac_openssldir='yes'
        
        AC_ARG_WITH(openssl,
            AC_HELP_STRING([--with-openssl=DIR],
                [location of an OpenSSL installation (default system)]),
            ac_openssldir=$withval)
        
        ac_save_LDFLAGS="$LDFLAGS"
        ac_save_LIBS="$LIBS"
        
        dnl
        dnl Now check if we have a cached value, unless the user specified
        dnl something explicit with the --with-openssl= argument, in
        dnl which case we force it to redo the checks (i.e. ignore the
        dnl cached values)
        dnl
        if test "$ac_openssldir" = yes -a ! x$openssl_cv_include = x ; then
            echo "checking for OpenSSL installation... (cached) $openssl_cv_include/openssl/evp.h, $openssl_cv_lib -lcrypto"
        else
            if test "$ac_openssldir" = system -o \
                    "$ac_openssldir" = yes -o \
                    "$ac_openssldir" = "" ; 
            then
                ac_openssldir="/usr/include"
                
                openssl_include=$ac_openssldir
                openssl_lib="/usr/lib"
            else
                openssl_include=$ac_openssldir/include
                CPPFLAGS="$ac_save_CPPFLAGS -I$openssl_include"
                openssl_lib=$ac_openssldir/lib
                LDFLAGS="$ac_save_LDFLAGS -L$openssl_lib"
           fi
            
        fi
        
        AC_CHECK_HEADERS([$openssl_include/openssl/evp.h], [], [AC_MSG_FAILURE([Cannot find OpenSSL.
       On Debian-based Linux systems, you need the 'libssl-dev' package.])])
        
        AC_CHECK_LIB([crypto], [EVP_DigestInit], [], [AC_MSG_FAILURE([Cannot find OpenSSL.
       On Debian-based Linux systems, you need the 'libssl-dev' package.])])
        
        AC_CHECK_LIB([crypto], [EVP_sha256], [], [AC_MSG_FAILURE([Cannot find EVP_sha256.
       On Mac OS X systems, you probably need an updated OpenSSL package, version 0.9.8.
       Specify   --with-openssl=/path/to/openssl LDFLAGS="-Wl,-search_paths_first"])])
    fi
])