Write the make_global_settings to the error message.

I'm trying to land some GN changes and get this error on various platforms with various configurations. Having the actual values that GYP and GN end up with for the make_global_settings will make troubleshooting much faster.

R=maruel@chromium.org

Review URL: https://codereview.chromium.org/104923014

git-svn-id: http://gyp.googlecode.com/svn/trunk@1827 78cadc50-ecff-11dd-a971-7dbc132099af
diff --git a/pylib/gyp/generator/make.py b/pylib/gyp/generator/make.py
index 8fb856f..9e82e68 100644
--- a/pylib/gyp/generator/make.py
+++ b/pylib/gyp/generator/make.py
@@ -2094,7 +2094,8 @@
 
     this_make_global_settings = data[build_file].get('make_global_settings', [])
     assert make_global_settings_array == this_make_global_settings, (
-        "make_global_settings needs to be the same for all targets.")
+        "make_global_settings needs to be the same for all targets. %s vs. %s" %
+        (this_make_global_settings, make_global_settings))
 
     build_files.add(gyp.common.RelativePath(build_file, options.toplevel_dir))
     included_files = data[build_file]['included_files']
diff --git a/pylib/gyp/generator/ninja.py b/pylib/gyp/generator/ninja.py
index d3db2c8..57acb23 100644
--- a/pylib/gyp/generator/ninja.py
+++ b/pylib/gyp/generator/ninja.py
@@ -2027,7 +2027,8 @@
 
     this_make_global_settings = data[build_file].get('make_global_settings', [])
     assert make_global_settings == this_make_global_settings, (
-        "make_global_settings needs to be the same for all targets.")
+        "make_global_settings needs to be the same for all targets. %s vs. %s" %
+        (this_make_global_settings, make_global_settings))
 
     spec = target_dicts[qualified_target]
     if flavor == 'mac':