Special-case paths that appear in libs by not prefixing them with -l.

tools/gn/variables.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "tools/gn/variables.h"
 
 namespace variables {
 
 // Built-in variables ----------------------------------------------------------
 
@@ skipping 874 matching lines @@
     "Example\n"
     "\n"
     "  lib_dirs = [ \"/usr/lib/foo\", \"lib/doom_melon\" ]\n";
 
 const char kLibs[] = "libs";
 const char kLibs_HelpShort[] =
     "libs: [string list] Additional libraries to link.";
 const char kLibs_Help[] =
     "libs: Additional libraries to link.\n"
     "\n"
-    "  A list of strings.\n"
+    "  A list of library names or library paths.\n"
     "\n"
-    "  These files will be passed to the linker, which will generally search\n"
-    "  the library include path. Unlike a normal list of files, they will be\n"
-    "  passed to the linker unmodified rather than being treated as file\n"
-    "  names relative to the current build file. Generally you would set\n"
-    "  the \"lib_dirs\" so your library is found. If you need to specify\n"
-    "  a path, you can use \"rebase_path\" to convert a path to be relative\n"
-    "  to the build directory.\n"
+    "Values containing '/' will be treated as references to files in the\n"
+    "build. They will be rebased to be relative to the build directory and\n"
+    "specified in the \"libs\" for linker tools. This facility should be used\n"
+    "for libraries that are checked in to the build. For libraries that are\n"
+    "generated by the build, use normal GN deps to link them.\n"
     "\n"
-    "  When constructing the linker command, the \"lib_prefix\" attribute of\n"
-    "  the linker tool in the current toolchain will be prepended to each\n"
-    "  library. So your BUILD file should not specify the switch prefix\n"
-    "  (like \"-l\").\n"
+    "Values not containing '/' will be treated as system library names. These\n"
+    "will be passed unmodified to the linker and prefixed with the\n"
+    "\"lib_prefix\" attribute of the linker tool. Generally you would set the\n"
+    "\"lib_dirs\" so the given library is found. Your BUILD.gn file should\n"
+    "not specify the switch prefix (like \"-l\"): this will be encoded in\n"
+    "the \"lib_prefix\" of the tool.\n"
     "\n"
     "  Libraries ending in \".framework\" will be special-cased: the switch\n"
     "  \"-framework\" will be prepended instead of the lib_prefix, and the\n"
     "  \".framework\" suffix will be trimmed. This is to support the way Mac\n"
     "  links framework dependencies.\n"
     COMMON_LIB_INHERITANCE_HELP
     COMMON_ORDERING_HELP
     LIBS_AND_LIB_DIRS_ORDERING_HELP
     "\n"
     "Examples\n"
@@ skipping 513 matching lines @@
     INSERT_VARIABLE(Sources)
     INSERT_VARIABLE(Testonly)
     INSERT_VARIABLE(Visibility)
   }
   return info_map;
 }
 
 #undef INSERT_VARIABLE
 
 }  // namespace variables