Set environment variables for reproducible build

PKGBUILD

@@ -41,6 +41,11 @@ build() {
     --sysconfdir=/etc/$pkgname
   )
 
+  # set environment variables for reproducible build
+  # see https://docs.prrte.org/en/latest/release-notes.html
+  export HOSTNAME=buildhost
+  export USER=builduser
+
   cd $pkgname-$pkgver
   ./configure "${configure_options[@]}"
   # prevent excessive overlinking due to libtool