sagemathgh-38088: Add `# sage_setup: distribution` directives for the files of existing distributions sagemath-{categories,...,tdlib}
    
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These directives at the top of the file inform developers about the
assignment of modules to pip-installable distributions.

As of this PR, there should be no change to the existing distributions
(sagemath-categories...) nor the monolithic build of the Sage library.

This is a portion of:
- sagemath#37901

In contrast to that PR, it has no dependencies.

### 📝 Checklist

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- [ ] I have updated the documentation and checked the documentation
preview.

### ⌛ Dependencies

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URL: sagemath#38088
Reported by: Matthias Köppe
Reviewer(s): Kwankyu Lee

Author: Release Manager

pkgs/sagemath-standard/setup.py

@@ -72,7 +72,11 @@
 # TODO: This should be quiet by default
 print("Discovering Python/Cython source code....")
 t = time.time()
-distributions = ['']
+distributions = ['sagemath-categories',
+                 'sagemath-environment',
+                 'sagemath-objects',
+                 'sagemath-repl',
+                 '']
 log.warn('distributions = {0}'.format(distributions))
 from sage_setup.find import find_python_sources
 python_packages, python_modules, cython_modules = find_python_sources(

src/sage/all__sagemath_categories.py

@@ -1,3 +1,4 @@
+# sage_setup: distribution = sagemath-categories
 from sage.all__sagemath_objects import *
 
 from sage.categories.all import *

src/sage/all__sagemath_environment.py

@@ -1,3 +1,4 @@
+# sage_setup: distribution = sagemath-environment
 from sage.env import SAGE_ROOT, SAGE_SRC, SAGE_DOC_SRC, SAGE_LOCAL, DOT_SAGE, SAGE_ENV
 
 from sage.misc.all__sagemath_environment import *

src/sage/all__sagemath_objects.py

@@ -1,3 +1,4 @@
+# sage_setup: distribution = sagemath-objects
 import os
 import sys
 import operator

src/sage/all__sagemath_repl.py

@@ -1,3 +1,5 @@
+# sage_setup: distribution = sagemath-repl
+
 # Set up warning filters before importing Sage stuff
 
 import sys

src/sage/arith/all__sagemath_objects.py

@@ -1,2 +1,3 @@
+# sage_setup: distribution = sagemath-objects
 # The presence of this file ensures that sage_setup for sagemath-objects
 # considers this directory as a namespace package

src/sage/arith/long.pxd

@@ -1,3 +1,4 @@
+# sage_setup: distribution = sagemath-objects
 # sage.doctest: needs sage.misc.cython
 r"""
 Fast conversion of Python objects to C long

src/sage/arith/numerical_approx.pxd

@@ -1,3 +1,4 @@
+# sage_setup: distribution = sagemath-objects
 # sage.doctest: needs sage.rings.real_mpfr
 
 cpdef inline long digits_to_bits(d) except -1:

src/sage/arith/numerical_approx.pyx

@@ -1,3 +1,4 @@
+# sage_setup: distribution = sagemath-objects
 # sage.doctest: needs sage.rings.real_mpfr
 r"""
 Generic numerical approximation function

src/sage/arith/power.pxd

@@ -1,3 +1,4 @@
+# sage_setup: distribution = sagemath-objects
 from cpython.number cimport PyNumber_TrueDivide
 from sage.structure.element cimport Element