comparable PYTHON_VERSION

[Thomas Klausner <wiz%NetBSD.org@localhost>]

Hi!

Some Python dependencies are only needed for particular python
versions, e.g. "anything before 3.10". Many packages currently use
something like

.include "../../lang/python/pyversion.mk"
.if ${_PYTHON_VERSION} < 310
DEPENDS+=...
.endif

but this has a couple problems:

a) _PYTHON_VERSION can be 'none' if the package-allowed and
   environment-allowed settings have no overlap, leading to

make: "/usr/pkgsrc/path/py-foo/Makefile" line 30: Comparison with '<' requires both operands 'none' and '311' to be numeric

b) the numbers are currently ordering well, but only by accident:
   27<37<38<39<310<311
   if 4.0=40 ever comes out, it will NOT sort well into this.

(c) variables with underscores are internal and not supposed to be used
    in package Makefiles)

The attached patch introduces a PYTHON_VERSION that solves all of
these. It's set to "major_version + 100 * minor_version".

a) it's 0 if there is no overlap (but I'd like to hear arguments if
999 would be a better value)

b) it sorts correctly now and will do so later:
   207<307<308<309<310<311<400

c) it doesn't start with an underscore

Comments, suggestions?
 Thomas

Index: pyversion.mk
===================================================================
RCS file: /cvsroot/pkgsrc/lang/python/pyversion.mk,v
retrieving revision 1.147
diff -u -r1.147 pyversion.mk
--- pyversion.mk	25 Mar 2023 18:29:44 -0000	1.147
+++ pyversion.mk	27 Mar 2023 20:11:47 -0000
@@ -139,9 +139,12 @@
 # No supported version found, annotate to simplify statements below.
 .if !defined(_PYTHON_VERSION)
 _PYTHON_VERSION=	none
+PYTHON_VERSION=		0
 PKG_FAIL_REASON+=	"No valid Python version"
 PYPKGPREFIX=		none
 PYVERSSUFFIX=		none
+.else
+PYTHON_VERSION=		${_PYTHON_VERSION:S/27/207/:S/37/307/:S/38/308/:S/39/309/}
 .endif
 
 # Additional CONFLICTS
@@ -240,7 +243,7 @@
 	PYTHON_VERSIONS_ACCEPTED PYTHON_VERSIONS_INCOMPATIBLE		\
 	PYTHON_SELF_CONFLICT PYTHON_FOR_BUILD_ONLY USE_CMAKE BUILD_USES_CMAKE
 _SYS_VARS.pyversion=	\
-	PYTHON_VERSION_REQD PYPACKAGE PYVERSSUFFIX PYPKGSRCDIR		\
+	PYTHON_VERSION PYTHON_VERSION_REQD PYPACKAGE PYVERSSUFFIX PYPKGSRCDIR		\
 	PYPKGPREFIX PYTHONBIN PYTHONCONFIG PY_COMPILE_ALL		\
 	PY_COMPILE_O_ALL PYINC PYLIB PYSITELIB CMAKE_ARGS
 _USE_VARS.pyversion=	\