bpo-36588: For AIX remove major version from sys.platform

Doc/library/sys.rst

@@ -1014,7 +1014,7 @@ always available.
    This string contains a platform identifier that can be used to append
    platform-specific components to :data:`sys.path`, for instance.
 
-   For Unix systems, except on Linux, this is the lowercased OS name as
+   For Unix systems, except on Linux and AIX, this is the lowercased OS name as
    returned by ``uname -s`` with the first part of the version as returned by
    ``uname -r`` appended, e.g. ``'sunos5'`` or ``'freebsd8'``, *at the time
    when Python was built*.  Unless you want to test for a specific system
@@ -1024,12 +1024,15 @@ always available.
           # FreeBSD-specific code here...
       elif sys.platform.startswith('linux'):
           # Linux-specific code here...
+      elif sys.platform.startswith('aix'):
+          # AIX-specific code here...
 
    For other systems, the values are:
 
    ================ ===========================
    System           ``platform`` value
    ================ ===========================
+   AIX              ``'aix'``
    Linux            ``'linux'``
    Windows          ``'win32'``
    Windows/Cygwin   ``'cygwin'``
@@ -1042,6 +1045,12 @@ always available.
       older Python versions include the version number, it is recommended to
       always use the ``startswith`` idiom presented above.
 
+   .. versionchanged:: 3.8
+      On AIX, :attr:`sys.platform` doesn't contain the major version anymore.
+      It is always ``'aix'``, instead of ``'aix5'`` or ``'aix7'``.  Since
+      older Python versions include the version number, it is recommended to
+      always use the ``startswith`` idiom presented above.
+
    .. seealso::
 
       :attr:`os.name` has a coarser granularity.  :func:`os.uname` gives

Doc/whatsnew/3.8.rst

@@ -700,6 +700,11 @@ Changes in Python behavior
   raised when getting the attribute from the type dictionary are no longer
   ignored.  (Contributed by Serhiy Storchaka in :issue:`35459`.)
 
+* On AIX, :attr:`sys.platform` doesn't contain the major version anymore.
+  It is always ``'aix'``, instead of ``'aix3'`` .. ``'aix7'``.  Since
+  older Python versions include the version number, it is recommended to
+  always use the ``sys.platform.startswith('aix')``.
+  (Contributed by M. Felt in :issue:`36588`.)
 
 Changes in the Python API
 -------------------------

Misc/NEWS.d/next/Core and Builtins/2019-04-11-14-36-55.bpo-36588.wejLoC.rst

@@ -0,0 +1,5 @@
+On AIX, :attr:`sys.platform` doesn't contain the major version anymore.
+Always return ``'aix'``, instead of ``'aix3'`` .. ``'aix7'``.  Since
+older Python versions include the version number, it is recommended to
+always use ``sys.platform.startswith('aix')``.
+Contributed by M. Felt.

configure

@@ -783,7 +783,6 @@ infodir
 docdir
 oldincludedir
 includedir
-runstatedir
 localstatedir
 sharedstatedir
 sysconfdir
@@ -895,7 +894,6 @@ datadir='${datarootdir}'
 sysconfdir='${prefix}/etc'
 sharedstatedir='${prefix}/com'
 localstatedir='${prefix}/var'
-runstatedir='${localstatedir}/run'
 includedir='${prefix}/include'
 oldincludedir='/usr/include'
 docdir='${datarootdir}/doc/${PACKAGE_TARNAME}'
@@ -1148,15 +1146,6 @@ do
   | -silent | --silent | --silen | --sile | --sil)
     silent=yes ;;
 
-  -runstatedir | --runstatedir | --runstatedi | --runstated \
-  | --runstate | --runstat | --runsta | --runst | --runs \
-  | --run | --ru | --r)
-    ac_prev=runstatedir ;;
-  -runstatedir=* | --runstatedir=* | --runstatedi=* | --runstated=* \
-  | --runstate=* | --runstat=* | --runsta=* | --runst=* | --runs=* \
-  | --run=* | --ru=* | --r=*)
-    runstatedir=$ac_optarg ;;
-
   -sbindir | --sbindir | --sbindi | --sbind | --sbin | --sbi | --sb)
     ac_prev=sbindir ;;
   -sbindir=* | --sbindir=* | --sbindi=* | --sbind=* | --sbin=* \
@@ -1294,7 +1283,7 @@ fi
 for ac_var in	exec_prefix prefix bindir sbindir libexecdir datarootdir \
 		datadir sysconfdir sharedstatedir localstatedir includedir \
 		oldincludedir docdir infodir htmldir dvidir pdfdir psdir \
-		libdir localedir mandir runstatedir
+		libdir localedir mandir
 do
   eval ac_val=\$$ac_var
   # Remove trailing slashes.
@@ -1447,7 +1436,6 @@ Fine tuning of the installation directories:
   --sysconfdir=DIR        read-only single-machine data [PREFIX/etc]
   --sharedstatedir=DIR    modifiable architecture-independent data [PREFIX/com]
   --localstatedir=DIR     modifiable single-machine data [PREFIX/var]
-  --runstatedir=DIR       modifiable per-process data [LOCALSTATEDIR/run]
   --libdir=DIR            object code libraries [EPREFIX/lib]
   --includedir=DIR        C header files [PREFIX/include]
   --oldincludedir=DIR     C header files for non-gcc [/usr/include]
@@ -3293,6 +3281,7 @@ then
     MACHDEP="$ac_md_system$ac_md_release"
 
     case $MACHDEP in
+	aix*) MACHDEP="aix";;
 	linux*) MACHDEP="linux";;
 	cygwin*) MACHDEP="cygwin";;
 	darwin*) MACHDEP="darwin";;
@@ -10211,7 +10200,6 @@ fi
 
 
 
-
 if test "x$ac_cv_env_PKG_CONFIG_set" != "xset"; then
 	if test -n "$ac_tool_prefix"; then
   # Extract the first word of "${ac_tool_prefix}pkg-config", so it can be a program name with args.

configure.ac

@@ -404,6 +404,7 @@ then
     MACHDEP="$ac_md_system$ac_md_release"
 
     case $MACHDEP in
+	aix*) MACHDEP="aix";;
 	linux*) MACHDEP="linux";;
 	cygwin*) MACHDEP="cygwin";;
 	darwin*) MACHDEP="darwin";;