printing: Invoke cups-config from the sysroot if one is being used.

printing/BUILD.gn

Index: printing/BUILD.gn
diff --git a/printing/BUILD.gn b/printing/BUILD.gn
index d8255be842de4e725a7145c28b9b333d23e8c082..45dfcc8e9399247f124ff09062ef51fe1a6a58d6 100644
--- a/printing/BUILD.gn
+++ b/printing/BUILD.gn
@@ -3,6 +3,7 @@
 # found in the LICENSE file.
 
 import("//build/config/features.gni")
+import("//build/config/sysroot.gni")
 import("//build/config/ui.gni")
 import("//testing/test.gni")
 if (is_mac) {
@@ -128,7 +129,10 @@ component("printing") {
 
     if (is_linux) {
       cups_version = exec_script("cups_config_helper.py",
-                                 [ "--api-version" ],
+                                 [
+                                   "--api-version",
+                                   sysroot,
+                                 ],
                                  "trim string")
 
       if (cups_version == "1.6" || cups_version == "1.7") {
@@ -247,7 +251,12 @@ if (use_cups) {
       libs = [ "cups" ]
       lib_dirs = [ "$mac_sdk_path/usr/lib" ]
     } else {
-      libs = exec_script("cups_config_helper.py", [ "--libs-for-gn" ], "value")
+      libs = exec_script("cups_config_helper.py",
+                         [
+                           "--libs-for-gn",
+                           sysroot,
+                         ],
+                         "value")
     }
   }
 }