1.1 --- a/configure.ac	Mon Jul 07 15:20:43 2008 +0100
     1.2 +++ b/configure.ac	Thu Jul 10 18:53:00 2008 +0100
     1.3 @@ -32,7 +32,16 @@
     1.4    export PKG_CONFIG_PATH="$with_lemon/lib/pkgconfig/:$PKG_CONFIG_PATH"
     1.5  fi
     1.6  
     1.7 -PKG_CHECK_MODULES([LEMON], [lemon >= 0.6.90])
     1.8 +PKG_CHECK_MODULES([LEMON], [lemon >= 0.6.90], [], [AC_MSG_ERROR([
     1.9 +No appropriate version of package 'lemon' found.
    1.10 +
    1.11 +Consider adjusting the PKG_CONFIG_PATH environment variable or using
    1.12 +the --with-lemon=PREFIX configure flag if you installed it in a
    1.13 +non-standard prefix.
    1.14 +
    1.15 +Alternatively, you may set the environment variables LEMON_CFLAGS and
    1.16 +LEMON_LIBS to avoid the need to call pkg-config.  See the pkg-config
    1.17 +man page for more details.])])
    1.18  
    1.19  dnl Checks for header files.
    1.20  AC_CHECK_HEADERS([libintl.h locale.h])