diff -Naur -x '*~' ephem-3.7.7.1/setup.py ephem-3.7.7.1-fix-linking/setup.py
--- ephem-3.7.7.1/setup.py	2020-02-22 23:22:07.000000000 +0100
+++ ephem-3.7.7.1-fix-linking/setup.py	2020-10-01 20:02:11.503069430 +0200
@@ -31,6 +31,7 @@
         + libastro_files + libastro_data,
         extra_compile_args=['-ffloat-store'],
         include_dirs=['libastro', '.'],
+        extra_link_args = ['-lm'],
         libraries = libraries,
     ),
 ]