Replace run_stuff with post/pre_<stage> variables.

If there's a file called "$pkgname.{pre,post}_{configure,build,install}
it will be automatically executed. In addition to this, templates may
use {pre,post}_{configure,build,install}_cmd variables to run arbitrary
commands.

--HG--
extra : convert_revision : 62ad549b8299689ecf8c833e73eda436ffdb7aa7

templates/syslinux.pre_build

@@ -0,0 +1,4 @@
+#
+# Disable looking for this file which causes an error.
+#
+sed -i -e 's|win32/syslinux.exe||g' $wrksrc/Makefile