Use all cores during build (#171)

* Use all cores during build

* Updated Authors

---------

Co-authored-by: Anton Sakhon <anton.sakhon@dataart.com>

AUTHORS

@@ -9,3 +9,4 @@ Michael Lamers (info@devmil.de)
 Andrea Daoud (andreadaoud6@gmail.com)
 Taha Firoz (mtahafiroz@gmail.com)
 Weiwei Duan (duanweiwei1982@gmail.com)
+Anton Sakhon (kofhein@gmail.com)

lib/elinux_build_target.dart

@@ -394,8 +394,18 @@ class NativeBundle {
       throwToolExit('Failed to cmake:\n$result');
     }
 
+    final procResult = await Process.run('nproc', []);
+
+    final numProc = procResult.stdout.toString().trim();
+
     result = await _processUtils.run(
-      <String>['cmake', '--build', '.'],
+      <String>[
+        'cmake',
+        '--build',
+        '.',
+        '--parallel',
+        numProc,
+      ],
       workingDirectory: outputDir.path,
     );
     if (result.exitCode != 0) {