sagemathgh-37671: pkgs/sagemath-standard: Support gpep517

    
From sagemath#37138 (comment)

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URL: sagemath#37671
Reported by: Matthias Köppe
Reviewer(s): François Bissey

pkgs/sagemath-standard/setup.py

@@ -64,7 +64,7 @@
 #########################################################
 
 if any(x in sys.argv
-       for x in ['build', 'bdist_wheel', 'install']):
+       for x in ['build', 'build_ext', 'bdist_wheel', 'install']):
     log.info("Generating auto-generated sources")
     from sage_setup.autogen import autogen_all
     autogen_all()