[libchamplain] Update README autotools building instructions

[Jiří Techet <jiritechet src gnome org>]

commit 062989ecb415e514446bf47f4fbf0b84895e0aad
Author: Jiří Techet <techet gmail com>
Date:   Thu Feb 7 13:44:04 2019 +0100

    Update README autotools building instructions
    
    configure won't be part of the tarball when using meson.

 README | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/README b/README
index 8158bdf..f4ee776 100644
--- a/README
+++ b/README
@@ -23,9 +23,9 @@ also need:
 
   *  libmemphis >= 0.2.1
 
-The usual rules for building apply -
+The usual rules for building apply:
 
-configure; make; sudo make install; sudo ldconfig
+./autogen.sh; make; sudo make install; sudo ldconfig
 
 should do the right thing. For more details consult the INSTALL file in this 
 directory. Alternatively, using the meson build system, run