diff --git a/configure.ac b/configure.ac
index 7f4a859..cf3f98b 100755
--- a/configure.ac
+++ b/configure.ac
@@ -2953,7 +2953,7 @@
         # Debian installs libxml headers under /usr/include/libxml2/libxml with
         # the shared library installed under /usr/lib, whereas the package
         # installs itself under $prefix/libxml and $prefix/lib.
-        xml2_prefix=`xml2-config --prefix`
+        xml2_prefix=`${xml2_config} --prefix`
         if test -d "${xml2_prefix}/include/libxml2"; then
             CPPFLAGS="$CPPFLAGS -I${xml2_prefix}/include/libxml2"
         fi