configure: fix to make older pkg-config play well

configure.ac:1349: error: possibly undefined macro: PKG_CONFIG_LIBDIR

Obviously this is not a problem with pkg-config 0.26 but older versions
seem to show this.

Fix suggested by: Kamil Dudka
Reported by: Guenter
Bug: http://curl.haxx.se/mail/lib-2011-11/0298.html

diff --git a/configure.ac b/configure.ac
index 52158f119145fe6247fb98cfd37173f4ff1272e9..7d2c7e4d5903d320f5f96c0c714024c32609f1c3 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -2377,6 +2377,10 @@ case "$LIBIDN" in
        fi
 
        if test "x$idn" != "xyes"; then
+
+         dnl to prevent errors with pkg-config < 0.26
+         m4_pattern_allow(PKG_CONFIG_LIBDIR)
+
          dnl check with pkg-config
          PKG_CHECK_MODULES(LIBIDN_PC, libidn >= 0.0.0, [idn=yes], [idn=no])
          if test "x$idn" = "xyes"; then