duk_config.h generated by replacing default in util/make_dist.py with:
# Build default duk_config.h from snippets using genconfig.
exec_print_stdout([
'python', os.path.join('config', 'genconfig.py'), '--metadata', 'config',
'--output', os.path.join(dist, 'duk_config.h.tmp'),
'--git-commit', git_commit, '--git-describe', git_describe, '--git-branch', git_branch,
'--omit-removed-config-options', '--omit-unused-config-options',
'--emit-config-sanity-check',
'--support-feature-options',
'--option-file', dist + '/../config/examples/performance_sensitive.yaml',
'--option-file', dist + '/../config/examples/timing_sensitive.yaml',
'duk-config-header'
])
... and then: python util/make_dist.py