bpo-1294959: Add sys.platlibdir attribute (GH-18381)

Add --with-platlibdir option to the configure script: name of the
platform-specific library directory, stored in the new sys.platlitdir
attribute. It is used to build the path of platform-specific dynamic
libraries and the path of the standard library.

It is equal to "lib" on most platforms. On Fedora and SuSE, it is
equal to "lib64" on 64-bit systems.
Co-Authored-By: Jan Matějek <jmatejek@suse.com>
Co-Authored-By: Matěj Cepl <mcepl@cepl.eu>
Co-Authored-By: Charalampos Stratakis <cstratak@redhat.com>

command/install.py

@@ -30,14 +30,14 @@ WINDOWS_SCHEME = {
 INSTALL_SCHEMES = {
     'unix_prefix': {
         'purelib': '$base/lib/python$py_version_short/site-packages',
-        'platlib': '$platbase/lib/python$py_version_short/site-packages',
+        'platlib': '$platbase/$platlibdir/python$py_version_short/site-packages',
         'headers': '$base/include/python$py_version_short$abiflags/$dist_name',
         'scripts': '$base/bin',
         'data'   : '$base',
         },
     'unix_home': {
         'purelib': '$base/lib/python',
-        'platlib': '$base/lib/python',
+        'platlib': '$base/$platlibdir/python',
         'headers': '$base/include/python/$dist_name',
         'scripts': '$base/bin',
         'data'   : '$base',
@@ -298,6 +298,7 @@ class install(Command):
                             'sys_exec_prefix': exec_prefix,
                             'exec_prefix': exec_prefix,
                             'abiflags': abiflags,
+                            'platlibdir': sys.platlibdir,
                            }
 
         if HAS_USER_SITE:

sysconfig.py

@@ -146,8 +146,15 @@ def get_python_lib(plat_specific=0, standard_lib=0, prefix=None):
             prefix = plat_specific and EXEC_PREFIX or PREFIX
 
     if os.name == "posix":
-        libpython = os.path.join(prefix,
-                                 "lib", "python" + get_python_version())
+        if plat_specific or standard_lib:
+            # Platform-specific modules (any module from a non-pure-Python
+            # module distribution) or standard Python library modules.
+            libdir = sys.platlibdir
+        else:
+            # Pure Python
+            libdir = "lib"
+        libpython = os.path.join(prefix, libdir,
+                                 "python" + get_python_version())
         if standard_lib:
             return libpython
         else:

tests/test_install.py

@@ -58,7 +58,8 @@ class InstallTestCase(support.TempdirManager,
 
         libdir = os.path.join(destination, "lib", "python")
         check_path(cmd.install_lib, libdir)
-        check_path(cmd.install_platlib, libdir)
+        platlibdir = os.path.join(destination, sys.platlibdir, "python")
+        check_path(cmd.install_platlib, platlibdir)
         check_path(cmd.install_purelib, libdir)
         check_path(cmd.install_headers,
                    os.path.join(destination, "include", "python", "foopkg"))