makepkg nosuchoption succeeds. No complains, package gets built

[u34--- via arch-general <arch-general@xxxxxxxxxxxxxxxxxxx>]

I was expecting for

    makepkg nosuchoption 

to fail. And complain. Instead, it succeeds. The package seem to get 
built.

The package involved is brscan4, from the AUR. All required files were 
already ownloaded, and in place.

    LC_ALL=C makepkg nosuchoption 

PKGBUILD looks to me short and rather simple.

    $ cat PKGBUILD
    # Maintainer: Harvey <harv@xxxxxx>
    license=('GPL' 'custom:Brother')
    arch=('i686' 'x86_64')
    pkgname=brscan4
    pkgver=0.4.10_1
    pkgrel=5
    pkgdesc="SANE drivers from Brother for brscan4 compatible models"
    depends=('sane' 'libusb-compat')
    url="http://support.brother.com";
    install=brscan4.install
    
    [ "$CARCH" = "x86_64" ] && pkg="dlf006648/${pkgname}-${pkgver/_/-}.x86_64.rpm" || pkg="dlf006647/${pkgname}-${pkgver/_/-}.i386.rpm"
    [ "$CARCH" = "x86_64" ] && pkg_md5sum="f4c4d1f214d4c42a6d40f5451fc40312" || pkg_md5sum="365f1b82ac3b7de73950be76a621bb93"
    
    source=("https://download.brother.com/welcome/$pkg";
    	"agree.html"
    	mk-udev-hwdb)
    md5sums=($pkg_md5sum
    	 'ccffb9a6f6d436b21be25b0241068981'
    	 '8966d38375d535028a63a6ef5f6104eb')
    
    build() {
      cd "$srcdir"
      ./mk-udev-hwdb opt/brother/scanner/brscan4/{Brsane4.ini,models4/*.ini} > hwdb
    }
    
    package() {
      cp -r $srcdir/etc $pkgdir
      cp -r $srcdir/opt $pkgdir
      cp -r $srcdir/usr $pkgdir
      [ "$CARCH" = "x86_64" ] && mv $pkgdir/usr/lib64 $pkgdir/usr/lib
      install -D -m644 $srcdir/agree.html $pkgdir/usr/share/licenses/$pkgname/LICENSE.html
      install -D -m644 $srcdir/hwdb $pkgdir/usr/lib/udev/hwdb.d/20-$pkgname.hwdb
      # move the links to the right direction
      cd $pkgdir/usr/lib/sane
      ln -sf libsane-brother4.so.1.0.7 $pkgdir/usr/lib/sane/libsane-brother4.so.1
      ln -sf libsane-brother4.so.1 $pkgdir/usr/lib/sane/libsane-brother4.so
    }

--
u34