Update libxml to 2.7.7.

third_party/libxml/patches/win32-clobber-makefile

Index: third_party/libxml/patches/win32-clobber-makefile
diff --git a/third_party/libxml/patches/win32-clobber-makefile b/third_party/libxml/patches/win32-clobber-makefile
new file mode 100644
index 0000000000000000000000000000000000000000..2f7fbb45eb7b9d113a2776c697dc2dff707e229a
--- /dev/null
+++ b/third_party/libxml/patches/win32-clobber-makefile
@@ -0,0 +1,19 @@
+Index: libxml/win32/configure.js
+===================================================================
+--- libxml.orig/win32/configure.js	2010-07-09 14:56:07.769093841 -0700
++++ libxml/win32/configure.js	2010-07-09 15:36:48.590268611 -0700
+@@ -611,7 +611,13 @@
+ 	makefile = ".\\Makefile.mingw";
+ else if (compiler == "bcb")
+ 	makefile = ".\\Makefile.bcb";
+-fso.CopyFile(makefile, ".\\Makefile", true);
++var new_makefile = ".\\Makefile";
++var f = fso.FileExists(new_makefile);
++if (f) {
++       var t = fso.GetFile(new_makefile);
++       t.Attributes = 0;
++}
++fso.CopyFile(makefile, new_makefile, true);
+ WScript.Echo("Created Makefile.");
+ // Create the config.h.
+ var confighsrc = "..\\include\\win32config.h";