Fix build on python <3.6

[percontation]

For reasons, I'm building xed under Debian Stretch which only has python3.5, which seems like it's supposed to work since mfile.py currently suggests that the build scripts work with python >= 3.4 https://github.com/intelxed/xed/blob/9fc12ab6c0ba7a9eaadb20135369b4b4107fa670/mfile.py#L89

But, it doesn't, since some f-strings (syntax feature added in python3.6) have crept into the build scripts.

The following patch appears to fix the issue for me:

--- mbuild/mbuild/util.py
+++ mbuild/mbuild/util.py
@@ -944,7 +944,7 @@ def get_clang_version(full_path):
         pass
     # Try the --version knob
     try:
-        (retcode, stdout, stderr) = run_command(f'{full_path} --version')
+        (retcode, stdout, stderr) = run_command(full_path + ' --version')
         if retcode == 0:
             for line in stdout:
                 r = re.search('version[ ]+(?P<version>(\d+\.)+\d+)', line.lower())
--- xed/xed_mbuild.py
+++ xed/xed_mbuild.py
@@ -152,7 +152,7 @@ class generator_inputs_t(object):
         found = False
         for f in list(self.files[file_type]):
             if os.path.samefile(f, file_name):
-                mbuild.vmsgb(1, f"REMOVE FILE ({file_type})", f)
+                mbuild.vmsgb(1, "REMOVE FILE (%s)" % file_type, f)
                 self.files[file_type].remove(f)
                 found = True
         if not found:
@@ -2570,7 +2570,7 @@ def _run_canned_tests(env,osenv):
     # Add additional tests (from cmd knob or layer's config files)
     for d in env['tests_ext']:
         mbuild.vmsgb(1, "ADDED TESTS EXT", d)
-        cmd += f" --tests {aq(d)}"
+        cmd += " --tests " + aq(d)

     # add test restriction/subetting codes
     codes = []

So, I'd suggest removing the incidental f-string usage as per that patch.

That, or raising the version check in mfile.py to indicate that python 3.6 is required, because currently, attempting to build with python <3.6 doesn't work, and also the build scripts swallow the relevant exception and return an incorrect error message about ./mbuild/ not being in the right place.

[marjevan]

Thanks for the report. I'll update the python requirement to 3.6. The update will be available with the next external release.