Reduce absolute paths in generated ninja files

build/config/gcc/BUILD.gn

Index: build/config/gcc/BUILD.gn
diff --git a/build/config/gcc/BUILD.gn b/build/config/gcc/BUILD.gn
index 433497e1350509e8fb0b715c70876adfb21ee980..66067dedf768226e361cdbca46aedaf03a22ed64 100644
--- a/build/config/gcc/BUILD.gn
+++ b/build/config/gcc/BUILD.gn
@@ -86,12 +86,12 @@ config("rpath_for_built_shared_libraries") {
       ldflags = [
         # Want to pass "\$". GN will re-escape as required for ninja.
         "-Wl,-rpath=\$ORIGIN/${rpath_link}",
-        "-Wl,-rpath-link=${rpath_link}",
+        "-Wl,-rpath-link=" + rebase_path(rpath_link, root_build_dir),

[brettw, 2017/05/30 03:57:56]

I don't understand this one, it looks like the input should already be relative
to the build dir. When does this one have an effect?

[wychen, 2017/05/30 06:34:05]

You are right. They don't have an effect.
Reverted.

Thanks for your eagle eye!

       ]
     } else {
       ldflags = [
         "-Wl,-rpath=${gcc_target_rpath}",
-        "-Wl,-rpath-link=${rpath_link}",
+        "-Wl,-rpath-link=" + rebase_path(rpath_link, root_build_dir),
       ]
     }
   }
@@ -134,7 +134,7 @@ config("executable_ldconfig") {
     }
 
     ldflags += [
-      "-Wl,-rpath-link=$_rpath_link",
+      "-Wl,-rpath-link=" + rebase_path(_rpath_link, root_build_dir),

[brettw, 2017/05/30 03:57:56]

Ditto here.

 
       # TODO(GYP): Do we need a check on the binutils version here?
       #