remove empty lines from PKGBUILD

Per the guidelines at https://wiki.archlinux.org/index.php/Arch_package_guidelines
removed the empty lines.

src/config/arch.rs

@@ -240,29 +240,73 @@ impl ArchConfig {
         add_data!("pkgrel={}\n", self.pkgrel);
         add_data!("epoch={}\n", self.epoch);
         add_data!("pkgdesc=\"{}\"\n", self.pkgdesc);
-        add_data!("url=\"{}\"\n", self.url);
-        add_data!("license=({})\n", quote_data(&self.license));
-        add_data!("install=\"{}\"\n", self.install);
-        add_data!("changelog=\"{}\"\n", self.changelog);
-        add_data!("source=({})\n", quote_data(&self.source));
-        add_data!("validpgpkeys=({})\n", quote_data(&self.validpgpkeys));
-        add_data!("noextract=({})\n", quote_data(&self.noextract));
-        add_data!("md5sums=({})\n", quote_data(&self.md5sums));
-        add_data!("sha1sums=({})\n", quote_data(&self.sha1sums));
-        add_data!("sha256sums=({})\n", quote_data(&self.sha256sums));
-        add_data!("sha384sums=({})\n", quote_data(&self.sha384sums));
-        add_data!("sha512sums=({})\n", quote_data(&self.sha512sums));
-        add_data!("groups=({})\n", quote_data(&self.groups));
+        if ! self.url.is_empty() {
+            add_data!("url=\"{}\"\n", self.url);
+        }
+        if ! self.license.is_empty() {
+            add_data!("license=({})\n", quote_data(&self.license));
+        }
+        if ! self.install.is_empty() {
+            add_data!("install=\"{}\"\n", self.install);
+        }
+        if ! self.changelog.is_empty() {
+            add_data!("changelog=\"{}\"\n", self.changelog);
+        }
+        if ! self.source.is_empty() {
+            add_data!("source=({})\n", quote_data(&self.source));
+        }
+        if ! self.validpgpkeys.is_empty() {
+            add_data!("validpgpkeys=({})\n", quote_data(&self.validpgpkeys));
+        }
+        if ! self.noextract.is_empty() {
+            add_data!("noextract=({})\n", quote_data(&self.noextract));
+        }
+        if ! self.md5sums.is_empty() {
+            add_data!("md5sums=({})\n", quote_data(&self.md5sums));
+        }
+        if ! self.sha1sums.is_empty() {
+            add_data!("sha1sums=({})\n", quote_data(&self.sha1sums));
+        }
+        if ! self.sha256sums.is_empty() {
+            add_data!("sha256sums=({})\n", quote_data(&self.sha256sums));
+        }
+        if ! self.sha384sums.is_empty() {
+            add_data!("sha384sums=({})\n", quote_data(&self.sha384sums));
+        }
+        if ! self.sha512sums.is_empty() {
+            add_data!("sha512sums=({})\n", quote_data(&self.sha512sums));
+        }
+        if ! self.groups.is_empty() {
+            add_data!("groups=({})\n", quote_data(&self.groups));
+        }
         add_data!("arch=({})\n", quote_data(&self.arch));
-        add_data!("backup=({})\n", quote_data(&self.backup));
-        add_data!("depends=({})\n", quote_data(&self.depends));
-        add_data!("makedepends=({})\n", quote_data(&self.makedepends));
-        add_data!("checkdepends=({})\n", quote_data(&self.checkdepends));
-        add_data!("optdepends=({})\n", quote_data(&self.optdepends));
-        add_data!("conflicts=({})\n", quote_data(&self.conflicts));
-        add_data!("provides=({})\n", quote_data(&self.provides));
-        add_data!("replaces=({})\n", quote_data(&self.replaces));
-        add_data!("options=({})\n", quote_data(&self.options));
+        if ! self.backup.is_empty() {
+            add_data!("backup=({})\n", quote_data(&self.backup));
+        }
+        if ! self.depends.is_empty() {
+            add_data!("depends=({})\n", quote_data(&self.depends));
+        }
+        if ! self.makedepends.is_empty() {
+            add_data!("makedepends=({})\n", quote_data(&self.makedepends));
+        }
+        if ! self.checkdepends.is_empty() {
+            add_data!("checkdepends=({})\n", quote_data(&self.checkdepends));
+        }
+        if ! self.optdepends.is_empty() {
+            add_data!("optdepends=({})\n", quote_data(&self.optdepends));
+        }
+        if ! self.conflicts.is_empty() {
+            add_data!("conflicts=({})\n", quote_data(&self.conflicts));
+        }
+        if ! self.provides.is_empty() {
+            add_data!("provides=({})\n", quote_data(&self.provides));
+        }
+        if ! self.replaces.is_empty() {
+            add_data!("replaces=({})\n", quote_data(&self.replaces));
+        }
+        if ! self.options.is_empty() {
+            add_data!("options=({})\n", quote_data(&self.options));
+        }
 
         buffer.push_str("\n");
         buffer.push_str(include_str!("PKGBUILD-TEMPLATE"));