Better error messages when no libidn

SRC/INSTALL

@@ -17,7 +17,7 @@ may not be available on your platform).
 --disable-http (suppress the HTTP support)
 --disable-smtp (suppress the SMTP support)
 --enable-icp   (add the ICP support, to monitor Web proxies like Squid)
---enable-idn   (add the IDN support, to handle Unicode domaine names, see RFC 3490)
+--disable-idn   (suppress the IDN support, the handling of Unicode domaine names, see RFC 3490)
 --with-gnutls[=/where/is/gnutls] (add the SSL/TLS support, you will need 
          the GNU TLS library <http://www.gnutls.org/>)
 --with-ssl[=/where/is/ssl] (add the SSL/TLS support, you will need 

SRC/acinclude.m4

@@ -180,7 +180,7 @@ AC_DEFUN([CF_LIB_GNUIDN],
 [
 AC_CHECK_LIB(idn,idna_to_ascii_from_utf8,
 [LIBS="${LIBS} `pkg-config libidn --libs-only-L` `pkg-config libidn --libs-only-l`"],
-[AC_ERROR([Get the GNU IDN library (http://www.josefsson.org/libidn/)])], dnl
+[AC_ERROR([Get the GNU IDN library (http://www.josefsson.org/libidn/) or use --disable-idn])], dnl
 )])
 
 dnl experimental

SRC/aclocal.m4

@@ -192,7 +192,7 @@ AC_DEFUN([CF_LIB_GNUIDN],
 [
 AC_CHECK_LIB(idn,idna_to_ascii_from_utf8,
 [LIBS="${LIBS} `pkg-config libidn --libs-only-L` `pkg-config libidn --libs-only-l`"],
-[AC_ERROR([Get the GNU IDN library (http://www.josefsson.org/libidn/)])], dnl
+[AC_ERROR([Get the GNU IDN library (http://www.josefsson.org/libidn/) or use --disable-idn])], dnl
 )])
 
 dnl experimental

SRC/configure

@@ -2140,7 +2140,7 @@ if eval "test \"`echo '$ac_cv_lib_'$ac_lib_var`\" = yes"; then
   LIBS="${LIBS} `pkg-config libidn --libs-only-L` `pkg-config libidn --libs-only-l`"
 else
   echo "$ac_t""no" 1>&6
-{ echo "configure: error: Get the GNU IDN library (http://www.josefsson.org/libidn/)" 1>&2; exit 1; }
+{ echo "configure: error: Get the GNU IDN library (http://www.josefsson.org/libidn/) or use --disable-idn" 1>&2; exit 1; }
 fi
 
 fi