fix(main/python): fix import _multiprocessing

- Fixes #28777
- #28768 , but for `import _multiprocessing`
- Restores pre-3.13 behavior of `python -c "import _multiprocessing"`
- Termux has implementation of `sem_open()` in `libandroid-posix-semaphore`

https://github.com/termux/termux-packages/blob/a68c38153da3cc6b338e1193f6b145ed65b5d1c1/packages/libandroid-posix-semaphore/semaphore.c#L89

Author: robertkirkman

packages/python/0005-impl-multiprocessing.patch

@@ -1,3 +1,19 @@
+sem_open() and sem_unlink() are implemented in Termux by libandroid-posix-semaphore
+https://github.com/termux/termux-packages/issues/28777
+
+--- a/configure.ac
++++ b/configure.ac
+@@ -5197,10 +5197,6 @@ if test "$ac_sys_system" = "Linux-android"; then
+   blocked_funcs="chroot initgroups setegid seteuid setgid sethostname
+     setregid setresgid setresuid setreuid setuid"
+ 
+-  # These functions are unimplemented and always return an error
+-  # (https://android.googlesource.com/platform/system/sepolicy/+/refs/heads/android13-release/public/domain.te#1044)
+-  blocked_funcs="$blocked_funcs sem_open sem_unlink"
+-
+   # Before API level 23, when fchmodat is called with the unimplemented flag
+   # AT_SYMLINK_NOFOLLOW, instead of returning ENOTSUP as it should, it actually
+   # follows the symlink.
 --- a/Lib/multiprocessing/heap.py
 +++ b/Lib/multiprocessing/heap.py
 @@ -70,7 +70,7 @@

packages/python/build.sh

@@ -5,7 +5,7 @@ TERMUX_PKG_LICENSE="custom"
 TERMUX_PKG_LICENSE_FILE="LICENSE"
 TERMUX_PKG_MAINTAINER="Yaksh Bariya <thunder-coding@termux.dev>"
 TERMUX_PKG_VERSION="3.13.12"
-TERMUX_PKG_REVISION=1
+TERMUX_PKG_REVISION=2
 _DEBPYTHON_COMMIT=f358ab52bf2932ad55b1a72a29c9762169e6ac47
 TERMUX_PKG_SRCURL=(
 	https://www.python.org/ftp/python/${TERMUX_PKG_VERSION}/Python-${TERMUX_PKG_VERSION}.tar.xz