Improved patch generation and versioning

PKGBUILD

@@ -1,5 +1,6 @@
 pkgname=libxft-bgra
-pkgver=2.3.3
+base_ver=2.3.3
+pkgver=2.3.3.r7.7808631e
 pkgrel=1
 pkgdesc="libXft with BGRA glyph (color emoji) rendering & scaling patches by Maxime Coste"
 arch=('x86_64')
@@ -9,28 +10,50 @@ provides=('libxft')
 conflicts=('libxft')
 url="https://xorg.freedesktop.org/"
 depends=('fontconfig' 'libxrender')
-makedepends=('pkgconfig')
+makedepends=('git' 'pkgconfig')
-source=(${url}/releases/individual/lib/libXft-${pkgver}.tar.bz2{,.sig}
+source=(${url}/releases/individual/lib/libXft-${base_ver}.tar.bz2{,.sig})
-	'https://gitlab.freedesktop.org/xorg/lib/libxft/merge_requests/1.patch')
 sha512sums=('28fdaf3baa3b156a4a7fdd6e39c4d8026d7d21eaa9be27c9797c8d329dab691a1bc82ea6042f9d4729a9343d93787536fb7e4b606f722f33cbe608b2e79910e8'
-            'SKIP'
             'SKIP')
 validpgpkeys=('4A193C06D35E7C670FA4EF0BA2FB9E081F2D130E') # "Alan Coopersmith <alan.coopersmith@oracle.com>"
 
+LIBXFT_UPSTREAM_URL="https://gitlab.freedesktop.org/xorg/lib/libxft.git"
+GITLAB_REVISION=7
+COMMIT_ID=7808631e7a9a605d5fe7a1077129c658d9ec47fc
+
+pkgver() {
+  echo "${base_ver}.r${GITLAB_REVISION}.`echo $COMMIT_ID | cut -c1-8`"
+}
+
 prepare() {
-  pushd libXft-${pkgver}
+  set -eo pipefail
-  patch -p1 < ../1.patch
+
+  # Create git repository to hold gitlab upstream code and create diff
+  if [ -d "libxft_upstream" ]; then
+    rm -rf "libxft_upstream";
+  fi;
+
+  mkdir libxft_upstream
+  pushd libxft_upstream
+  git init
+  git remote add upstream ${LIBXFT_UPSTREAM_URL}
+  git fetch --depth=2 upstream ${COMMIT_ID}
   popd
+
+  pushd libXft-${base_ver}
+  git --git-dir ../libxft_upstream/.git diff -u ${COMMIT_ID}~ ${COMMIT_ID} | patch -p1
+  popd
+
+  set +eo pipefail
 }
 
 build() {
-  cd libXft-${pkgver}
+  cd libXft-${base_ver}
   ./configure --prefix=/usr --sysconfdir=/etc --disable-static
   make
 }
 
 package() {
-  cd libXft-${pkgver}
+  cd libXft-${base_ver}
   make DESTDIR="${pkgdir}" install
   install -d -m755 "${pkgdir}/usr/share/licenses/${pkgname}"
   install -m644 COPYING "${pkgdir}/usr/share/licenses/${pkgname}/"