Point to build requirements page when there is a dependency check failure.

Tools/Scripts/webkitpy/layout_tests/port/base.py

Index: Tools/Scripts/webkitpy/layout_tests/port/base.py
diff --git a/Tools/Scripts/webkitpy/layout_tests/port/base.py b/Tools/Scripts/webkitpy/layout_tests/port/base.py
index ec0853a26c1d22071f62cd8cc45b1aea60684025..d7cde1c62d51e39467a7a3a78892362d302144c5 100644
--- a/Tools/Scripts/webkitpy/layout_tests/port/base.py
+++ b/Tools/Scripts/webkitpy/layout_tests/port/base.py
@@ -130,6 +130,9 @@ class Port(object):
 
     SUPPORTED_VERSIONS = []
 
+    # URL to the build requirements page.
+    BUILD_REQUIREMENTS_URL = ''
+
     @classmethod
     def latest_platform_fallback_path(cls):
         return cls.FALLBACK_PATHS[cls.SUPPORTED_VERSIONS[-1]]
@@ -383,6 +386,10 @@ class Port(object):
             _log.error('To override, invoke with --nocheck-sys-deps')
             _log.error('')
             _log.error(output)
+            if self.BUILD_REQUIREMENTS_URL is not '':
+                _log.error('')
+                _log.error('For complete build requirements, please see:')
+                _log.error(self.BUILD_REQUIREMENTS_URL)
             return test_run_results.SYS_DEPS_EXIT_STATUS
         return test_run_results.OK_EXIT_STATUS