as seen in GYP3 this seems to be the solution here too

dothebart · Oct 17, 2019 · b695898 · b695898
1 parent 34dcfad
commit b695898
Showing 1 changed file with 1 addition and 0 deletions.
diff --git a/gyp/pylib/gyp/input.py b/gyp/pylib/gyp/input.py
@@ -911,6 +911,7 @@ def ExpandVariables(input, phase, variables, build_file):
           p_stdout, p_stderr = p.communicate('')
 
           if p.wait() != 0 or p_stderr:
+            sys.stderr.write(p_stderr.decode('utf-8'))
             raise GypError("Call to '%s' returned exit status %d while in %s." %
                            (contents, p.returncode, build_file))
           replacement = p_stdout.rstrip()