Add a libcap target to link against libcap2.

build/linux/system.gyp

Index: build/linux/system.gyp
diff --git a/build/linux/system.gyp b/build/linux/system.gyp
index 0f294223936461f6f69ee4954e86b34a63915cd9..b462a3bc57447ffd3553a18606b6394a888f1c4f 100644
--- a/build/linux/system.gyp
+++ b/build/linux/system.gyp
@@ -883,5 +883,14 @@
         }],
       ],
     },
+    {
+      'target_name': 'libcap',

[Paweł Hajdan Jr., 2013/10/30 00:22:58]

nit: Please keep the list of targets sorted alphabetically, move this up to
match sort order.

[jln (very slow on Chromium), 2013/10/30 00:33:34]

Done.

+      'type': 'none',
+      'link_settings': {
+        'libraries': [
+          '-lcap',
+        ],
+      },
+    },
   ],
 }