diff --git a/ChangeLog b/ChangeLog
index 0f49985f..575f09d0 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2001-08-13  Pascal Bart  <pascal.bart@epita.fr>
+
+	* tests/atconfig.in (CPPFLAGS): Fix.
+
 2001-08-10  Pascal Bart  <pascal.bart@epita.fr>
 
 	* doc/bison.texinfo: Include GNU General Public License from
diff --git a/tests/atconfig.in b/tests/atconfig.in
index 29d893b2..3d1bb789 100644
--- a/tests/atconfig.in
+++ b/tests/atconfig.in
@@ -85,7 +85,9 @@ M4='@M4@'
 # We need a C compiler.
 CC='@CC@'
 CFLAGS='@CFLAGS@'
-CPPFLAGS='-I@top_srcdir@ @CPPFLAGS@'
+
+# We need `config.h'.
+CPPFLAGS="-I$at_top_builddir @CPPFLAGS@"
 
 # We want to use the files shipped with Bison.
 BISON_SIMPLE=$at_top_srcdir/src/bison.simple