Linux: clean up the usage of "use_cups" gyp switch:

printing/printing.gyp

Index: printing/printing.gyp
===================================================================
--- printing/printing.gyp	(revision 82994)
+++ printing/printing.gyp	(working copy)
@@ -125,6 +125,16 @@
           ],
         }],
         ['use_cups==1', {
+          'dependencies': [
+            'cups',
+          ],
+          'conditions': [
+            ['OS!="mac"', {
+              'dependencies': [
+                '../build/linux/system.gyp:libgcrypt',
+              ],
+            }],
+          ],
           'defines': [
             # PRINT_BACKEND_AVAILABLE disables the default dummy implementation
             # of the print backend and enables a custom implementation instead.
@@ -135,22 +145,6 @@
             'backend/cups_helper.h',
             'backend/print_backend_cups.cc',
           ],
-          'conditions': [
-            ['OS=="mac"', {
-              'link_settings': {
-                'libraries': [
-                  '$(SDKROOT)/usr/lib/libcups.dylib',
-                ]
-              },
-            }, {
-              'link_settings': {
-                'libraries': [
-                  '-lcups',
-                  '-lgcrypt',
-                ],
-              },
-            }],
-          ],
         }],
       ],
     },
@@ -201,6 +195,40 @@
         }],
       ],
     },
+    {
+      'target_name': 'cups',
+      'type': 'none',
+      'conditions': [
+        ['use_cups==1', {
+          'direct_dependent_settings': {
+            'defines': [
+              'USE_CUPS',
+            ],
+            'cflags': [
+              '<!@(cups-config --cflags)',

[Mark Mentovai, 2011/04/28 14:17:28]

I’d like to avoid running cups-config at all on the Mac, where it’s pointless
and returns empty strings anyway.

[Paweł Hajdan Jr., 2011/04/28 15:07:39]

Done.

+            ],
+            'ldflags': [
+              '<!@(cups-config --ldflags)',
+            ],
+            'conditions': [
+              ['OS=="mac"', {
+                'link_settings': {
+                  'libraries': [
+                    '$(SDKROOT)/usr/lib/libcups.dylib',
+                  ]
+                },
+              }, {
+                'link_settings': {
+                  'libraries': [
+                    '<!@(cups-config --libs)',
+                  ],
+                },
+              }],
+            ],
+          },
+        }],
+      ],
+    },
   ],
 }