Update Win32 configure.js to search for configure.ac
as configure.in was renamed
diff --git a/win32/configure.js b/win32/configure.js
index edd943a..92b9ba0 100644
--- a/win32/configure.js
+++ b/win32/configure.js
@@ -14,7 +14,7 @@
var baseName = "libxml2";
/* Configure file which contains the version and the output file where
we can store our build configuration. */
-var configFile = srcDirXml + "\\configure.in";
+var configFile = srcDirXml + "\\configure.ac";
var versionFile = ".\\config.msvc";
/* Input and output files regarding the libxml features. */
var optsFileIn = srcDirXml + "\\include\\libxml\\xmlversion.h.in";