opengtl: rebuild for libpng-1.6.3

opengtl/PKGBUILD

@@ -3,28 +3,29 @@
 
 pkgname=opengtl
 pkgver=0.9.18
-pkgrel=2
+pkgrel=3
 pkgdesc="A set of library for using and integrating transformation algorithms (such as filter or color conversion) in graphics applications"
 url="http://www.opengtl.org"
-arch=('i686' 'x86_64')
+arch=('x86_64')
 license=('GPL')
 depends=('gcc-libs' 'llvm')
 makedepends=('cmake' 'libpng')
 optdepends=('libpng: for using the png extension')
-source=(http://download.opengtl.org/OpenGTL-${pkgver}.tar.bz2
-        opengtl-0.9.18-llvm-3.3.patch
-        opengtl-0.9.18-memcpy.patch)
+source=("http://download.opengtl.org/OpenGTL-${pkgver}.tar.bz2"
+        "opengtl-0.9.18-llvm-3.3.patch"
+        "opengtl-0.9.18-memcpy.patch")
 sha256sums=('f094b3d2a1a60519975bb3badc05e704f2b93c7a3d2cb753041f2ff27cfcd9f8'
             'c43418bc039660ae86cb86b8b8175342793cb1361c699faa9b6342bc896e3d6c'
             '934f2d3b0452b0505d0b4a39f2f9022ea490be12eda77d46caf0d66eabef59f3')
 
-build() {
-  cd "${srcdir}"
-  mkdir build
+prepare() {
   patch -d OpenGTL-$pkgver -Np1 -i "$srcdir/opengtl-0.9.18-memcpy.patch"
   # Fix build with LLVM 3.3 (patch from Fedora)
   patch -d OpenGTL-$pkgver -Np1 -i "$srcdir/opengtl-0.9.18-llvm-3.3.patch"
-  cd build
+}
+            
+build() {
+  mkdir -p build && cd build
   cmake ../OpenGTL-${pkgver} \
                 -DCMAKE_BUILD_TYPE=Release \
                 -DCMAKE_SKIP_RPATH=ON \
@@ -33,6 +34,6 @@ build() {
 }
 
 package() {
-  cd "${srcdir}/build"
+  cd build
   make DESTDIR="${pkgdir}" install
 }