patch to allow venv creation from symlinks

Patch CPython to allow venvs to be created from symlinks.
When inside a venv and base_executable is passed available. Use the
resolved path as the executable_dir rather than the one specified by
home in pyvenv.cfg

Author: jjhelmus

cpython-unix/build-cpython.sh

@@ -636,6 +636,12 @@ if [[ -n "${PYTHON_MEETS_MINIMUM_VERSION_3_14}" ]]; then
     patch -p1 -i "${ROOT}/patch-python-getpath-3.14.patch"
 fi
 
+# Another, similar change to getpath: When reading inside a venv use the base_executable path to
+# determine executable_dir when valid. This allows venv to be created from symlinks and covers some
+# cases the above patch doesn't. See:
+# https://github.com/python/cpython/issues/106045#issuecomment-2594628161
+patch -p1 -i "${ROOT}/patch-getpath-use-base_executable-for-executable_dir.patch"
+
 # We patched configure.ac above. Reflect those changes.
 autoconf
 

cpython-unix/patch-getpath-use-base_executable-for-executable_dir.patch

@@ -0,0 +1,14 @@
+diff --git a/Modules/getpath.py b/Modules/getpath.py
+index ceb605a75c8..164d708ffca 100644
+--- a/Modules/getpath.py
++++ b/Modules/getpath.py
+@@ -411,6 +411,9 @@ def search_up(prefix, *landmarks, test=isfile):
+                             if isfile(candidate):
+                                 base_executable = candidate
+                                 break
++                if base_executable and isfile(base_executable):
++                    # Update the executable directory to be based on the resolved base executable
++                    executable_dir = real_executable_dir = dirname(base_executable)
+             # home key found; stop iterating over lines
+             break
+