make gtk2 an optdepends

.SRCINFO

@@ -1,7 +1,7 @@
 pkgbase = brscan4
 	pkgdesc = SANE drivers from Brother for compatible models
 	pkgver = 0.4.11_1
-	pkgrel = 1
+	pkgrel = 2
 	url = http://support.brother.com
 	install = brscan4.install
 	arch = i686
@@ -9,7 +9,7 @@ pkgbase = brscan4
 	license = GPL
 	license = custom:Brother
 	depends = sane
-	depends = gtk2
+	optdepends = gtk2: for using brscan_gnetconfig
 	source = https://download.brother.com/welcome/dlf105203/brscan4-0.4.11-1.x86_64.rpm
 	source = agree.html
 	source = mk-udev-hwdb

PKGBUILD

@@ -3,9 +3,10 @@ license=('GPL' 'custom:Brother')
 arch=('i686' 'x86_64')
 pkgname=brscan4
 pkgver=0.4.11_1
-pkgrel=1
+pkgrel=2
 pkgdesc="SANE drivers from Brother for compatible models"
-depends=('sane' 'gtk2')
+depends=('sane')
+optdepends=('gtk2: for using brscan_gnetconfig')
 url="http://support.brother.com"
 install=brscan4.install