Linux: add option to link libpci directly instead of using dlopen.

build/linux/system.gyp

Index: build/linux/system.gyp
diff --git a/build/linux/system.gyp b/build/linux/system.gyp
index 2eacbdbaaba56db8f5633e7a63ef3d78dc8cae5c..d360b9857e0efcc107f39e1786819adeea758b1f 100644
--- a/build/linux/system.gyp
+++ b/build/linux/system.gyp
@@ -275,6 +275,37 @@
       ],
     },
     {
+      'target_name': 'libpci',
+      'type': 'none',
+      'direct_dependent_settings': {
+        'cflags': [
+          '<!@(<(pkg-config) --cflags libpci)',
+        ],
+        'conditions': [
+          ['linux_link_libpci==0', {
+            'defines': ['DLOPEN_LIBPCI'],
+          }],
+        ],
+      },
+      'link_settings': {
+        'conditions': [
+          ['linux_link_libpci==0 and OS=="linux"', {
+            'libraries': [
+              '-ldl',
+            ],
+          }],
+          ['linux_link_libpci==1', {
+            'ldflags': [
+              '<!@(<(pkg-config) --libs-only-L --libs-only-other libpci)',
+            ],
+            'libraries': [
+              '<!@(<(pkg-config) --libs-only-l libpci)',
+            ],
+          }],
+        ],
+      },
+    },
+    {
       'target_name': 'x11',
       'type': 'none',
       'toolsets': ['host', 'target'],