gh-38910: Meson: minor revision
    
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A bit of a minor cleanup of the meson build files. Extracted from
#38872.

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preview.

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URL: #38910
Reported by: Tobias Diez
Reviewer(s): Michael Orlitzky

Author: Release Manager

.gitignore

@@ -312,6 +312,7 @@ build-install
 build/cp*
 
 # Meson temporary files
+subprojects/wrapdb.json
 src/sage/interfaces/__init__.py
 src/sage/crypto/block_cipher/__init__.py
 src/sage/crypto/public_key/__init__.py

meson.build

@@ -35,7 +35,7 @@ endif
 
 # Workaround for missing init files (Cython doesn't handle namespace packages well)
 create_files_command = [
-  'python3',
+  py,
   '-c',
   '''
 import os

src/meson.build

@@ -80,7 +80,6 @@ blas_order += ['cblas', 'openblas', 'OpenBLAS', 'flexiblas', 'blis', 'blas']
 blas = dependency(blas_order)
 gsl = dependency(
   'gsl',
-  fallback: ['gsl', 'gsl_dep'],
   version: '>=2.5',
   required: true,
 )

src/sage/meson.build

@@ -6,7 +6,7 @@ conf_data = configuration_data()
 conf_data.set('PACKAGE_VERSION', '1.2.3')
 conf_data.set('SAGE_ROOT', meson.current_source_dir() / '..' / '..')
 # We use Python's prefix here to make it work with conda
-prefix = py.get_variable('prefix', '')
+prefix = fs.as_posix(py.get_variable('prefix', ''))
 conf_data.set('prefix', prefix)
 datadir = fs.expanduser(get_option('datadir'))
 if not fs.is_absolute(datadir)
@@ -56,7 +56,7 @@ ecm_bin = find_program(['ecm', 'gmp-ecm'], required: true)
 conf_data.set('SAGE_ECMBIN', ecm_bin.full_path())
 
 config_file = configure_file(
-  input: '../../pkgs/sage-conf_conda/_sage_conf/_conf.py.in',
+  input: '../../pkgs/sage-conf/_sage_conf/_conf.py.in',
   output: 'config.py',
   install_dir: py.get_install_dir() / 'sage',
   install: true,