overrides "setup.py sdist" command to compile translation catalogs first

setup.py

@@ -1,6 +1,8 @@
 import os
+import subprocess
 
 import setuptools
+from setuptools.command.sdist import sdist
 
 with open("README.md", "r") as fh:
     long_description = fh.read()
@@ -12,6 +14,20 @@
 for name in os.listdir("./securedrop_client/resources/images/"):
     package_resources.append(os.path.join("./securedrop_client/resources/images", name))
 
+
+class SdistWithTranslationCatalogs(sdist):
+    def run(self):
+        """Call out to `make compile-translation-catalogs`, then run the rest of
+        the rest of the normal `sdist` routine.
+        """
+
+        cmd = ["make", "compile-translation-catalogs"]
+        if subprocess.call(cmd) != 0:
+            raise EnvironmentError(f"error calling {cmd}")
+
+        super().run()
+
+
 setuptools.setup(
     name="securedrop-client",
     version="0.5.0",
@@ -35,4 +51,9 @@
         "Operating System :: OS Independent",
     ),
     entry_points={"console_scripts": ["sd-client = securedrop_client.app:run"]},
+    # Override "sdist" to compile gettext gettext POs to MOs for inclusion in
+    # built distributions.
+    cmdclass={"sdist": SdistWithTranslationCatalogs},
+    package_data={"": ["locale/*/*/*.mo", "locale/*/*/*.po"]},
+    setup_requires=["babel"],
 )