Add --enable-cross-run configure option to avoid clearing RUNSHARED on cross-compile

Author: zanieb

Doc/using/configure.rst

@@ -1210,6 +1210,20 @@ the version of the cross compiled host Python.
 
    .. versionadded:: 3.11
 
+.. option:: --enable-cross-run
+
+   Enable running the target CPython binary on the build host during
+   cross-compilation.
+
+   By default, the build system assumes that target binaries cannot be executed
+   on the build host when cross-compiling which can disable optimizations such
+   as PGO.
+
+   When `--enable-cross-run` is used, the build system may attempt to execute
+   the target binaries, which is appropriate for situations where emulated
+   execution is transparently available.
+
+   .. versionadded:: 3.15
 
 Cross compiling example::
 

Misc/NEWS.d/next/Build/2025-11-24-17-01-16.gh-issue-141926.Rcxj2J.rst

@@ -0,0 +1,2 @@
+Add ```--enable-cross-run`` to allow execution of the target binary (e.g.,
+for PGO) during cross-compilation.

configure

@@ -1630,8 +1630,21 @@ else # shared is disabled
 fi
 AC_MSG_RESULT([$LDLIBRARY])
 
+# Check for --enable-cross-run
+AC_ARG_ENABLE([cross-run],
+  [AS_HELP_STRING([--enable-cross-run],
+    [allow running target binaries during cross-compilation (for PGO, etc.)])
+AS_HELP_STRING([--disable-cross-run],
+    [disable running target binaries during cross-compilation (default)])],
+  [],
+  [enable_cross_run=no])
+
 if test "$cross_compiling" = yes; then
-  RUNSHARED=
+  AC_MSG_CHECKING([whether to keep RUNSHARED for cross build])
+  AS_IF([test "$enable_cross_run" = yes],
+    [AC_MSG_RESULT([yes (--enable-cross-run)])],
+    [RUNSHARED=
+     AC_MSG_RESULT([no])])
 fi
 
 # HOSTRUNNER - Program to run CPython for the host platform