js185 is a very odd module:

  <autotools id="js185" check-target="false"
             autogenargs="--enable-threadsafe --with-system-nspr">
    <pkg-config>mozjs185.pc</pkg-config>
    <branch repo="ftp.mozilla.org"
            module="js/js185-1.0.0.tar.gz"
            version="1.0.0"
            checkoutdir="js185-1.0.0"
            source-subdir="js/src"
            md5sum="a4574365938222adca0a6bd33329cb32" size="6164605">
      <patch file="js185.destdir.patch" strip="0"/>
    </branch>
    <dependencies>
      <dep package="nspr"/>
    </dependencies>
  </autotools>


Unfortunately, when using checkout_mode = 'clobber', the source directory that gets erased before the checkout is the js/src subdirectory.  This makes it impossible to extract a second copy of the source (since the toplevel js185-1.0.0 directory is still there).  That causes the build to fail.

This would also impact the "wipe directory and start over" option, I suspect.

We need wipedir() to effect the toplevel directory, not the source subdirectory.