[MIPS] Fix issue with sysroot_ld_path.py returning empty string

build/config/posix/BUILD.gn

 # Copyright 2015 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.
 
 import("//build/config/sanitizers/sanitizers.gni")
 import("//build/config/sysroot.gni")
 import("//build/toolchain/toolchain.gni")
 
 assert(is_posix)
 
@@ skipping 20 matching lines @@
 # that is Posix-only. Please see that target for advice on what should go in
 # :runtime_library vs. :compiler.
 config("runtime_library") {
   if (!is_mac && !is_ios && sysroot != "") {
     # Pass the sysroot to all C compiler variants, the assembler, and linker.
     cflags = [ "--sysroot=" + rebase_path(sysroot, root_build_dir) ]
     asmflags = cflags
     ldflags = cflags
 
     # Need to get some linker flags out of the sysroot.
-    ldflags += [ exec_script("sysroot_ld_path.py",
-                             [
-                               rebase_path("//build/linux/sysroot_ld_path.sh",
-                                           root_build_dir),
-                               sysroot,
-                             ],
-                             "value") ]
+    ldflags += exec_script("sysroot_ld_path.py",
+                           [
+                             rebase_path("//build/linux/sysroot_ld_path.sh",
+                                         root_build_dir),
+                             rebase_path(sysroot),
+                           ],
+                           "list lines")
   }
 }