message: Fix autoheader failure on missing autogen/ subdir
diff: @@ -13,7 +13,7 @@ AC_CONFIG_MACRO_DIR([builds/autoconf/m4])
  AC_CONFIG_SRCDIR([src/data.cpp])
  # We want our public lcf/config.h to look like the cmake one. This tricks autoheader into generating
  # /config.h (which we don't use) and then configure uses our template for lcf/config.h
  -AC_CONFIG_HEADERS([autogen/config.h autogen/lcf/config.h:builds/autoconf.config.h.in])
  +AC_CONFIG_HEADERS([autogen/config.h:config.h.in autogen/lcf/config.h:builds/autoconf.config.h.in])
  AC_LANG([C++])
  # Checks for programs.
  