More docs

Author: tiran

Doc/using/configure.rst

@@ -513,6 +513,56 @@ See ``Mac/README.rst``.
    :option:`--enable-framework` is set (default: ``Python``).
 
 
+Cross Compiling Options
+-----------------------
+
+Cross compiling, also known as cross building, can be used to build Python
+for another CPU architecture or platform. Cross compiling requires a Python
+interpreter and the :program:`_freeze_module` binary from another build. The
+version of the build Python and :program:`_freeze_module` command must be
+the same as the cross compiled host Python.
+
+.. cmdoption:: --build=BUILD
+
+   configure for building on BUILD, usually guessed by :program:`config.guess`.
+
+.. cmdoption:: --host=HOST
+
+   cross-compile to build programs to run on HOST (target platform)
+
+.. cmdoption:: --with-freeze-module=Programs/_freeze_module
+
+   path to ``_freeze_module`` binary for cross compiling.
+
+   .. versionadded:: 3.11
+
+.. cmdoption:: --with-build-python=python3.xx
+
+   path to build ``python`` binary for cross compiling
+
+   .. versionadded:: 3.11
+
+.. cmdoption:: CONFIG_SITE=file
+
+   An environment variable that points to a file with configure overrides.
+
+   Example *config.site* file::
+
+      # config.site-aarch64
+      ac_cv_buggy_getaddrinfo=no
+      ac_cv_file__dev_ptmx=yes
+      ac_cv_file__dev_ptc=no
+
+
+Cross compiling example::
+
+   CONFIG_SITE=config.site-aarch64 ../configure \
+       --build=x86_64-pc-linux-gnu \
+       --host=aarch64-unknown-linux-gnu \
+       --with-freeze-module=../x86_64/Programs/_freeze_module \
+       --with-build-python=../x86_64/python
+
+
 Python Build System
 ===================
 

configure

@@ -1726,10 +1726,9 @@ Optional Packages:
   --without-PACKAGE       do not use PACKAGE (same as --with-PACKAGE=no)
   --with-freeze-module=Programs/_freeze_module
                           path to _freeze_module binary for cross compiling
-                          (default: self-hosted Programs/_freeze_module
-                          binary)
-  --with-build-python     path to build python binary for cross compiling
-                          (default: self-hosted ./python binary)
+  --with-build-python=python3.11
+                          path to build python binary for cross compiling
+                          (default: python3.11)
   --with-pkg-config=[yes|no|check]
                           use pkg-config to detect build options (default is
                           check)
@@ -3195,13 +3194,16 @@ fi
 rm -f pybuilddir.txt
 
 
-# Check whether --with-freeze_module was given.
+# Check whether --with-freeze-module was given.
 if test "${with_freeze_module+set}" = set; then :
   withval=$with_freeze_module;
     { $as_echo "$as_me:${as_lineno-$LINENO}: checking for --with-freeze-module" >&5
 $as_echo_n "checking for --with-freeze-module... " >&6; }
-        if test "$with_freeze_module" = yes -o "$with_freeze_module" = no; then
-      as_fn_error $? "invalid --with-freeze-module option: expect path, not \"$with_freeze_module\"" "$LINENO" 5
+    if test "x$cross_compiling" = xno; then :
+  as_fn_error $? "--with-freeze-module only applies to cross compiling" "$LINENO" 5
+fi
+    if test "$with_freeze_module" = yes -o "$with_freeze_module" = no; then
+      as_fn_error $? "invalid --with-freeze-module option: expected path, not \"$with_freeze_module\"" "$LINENO" 5
     fi
     if ! $(command -v "$with_freeze_module" >/dev/null 2>&1); then
       as_fn_error $? "invalid or missing freeze module binary \"$with_freeze_module\"" "$LINENO" 5
@@ -3229,20 +3231,28 @@ if test "${with_build_python+set}" = set; then :
   withval=$with_build_python;
     { $as_echo "$as_me:${as_lineno-$LINENO}: checking for --with-build-python" >&5
 $as_echo_n "checking for --with-build-python... " >&6; }
-        if test "$with_build_python" = yes -o "$with_build_python" = no; then
-      as_fn_error $? "invalid --with-freeze-module option: expect path, not \"$with_build_python\"" "$LINENO" 5
-    fi
+
+    if test "x$cross_compiling" = xno; then :
+  as_fn_error $? "--with-build-python only applies to cross compiling" "$LINENO" 5
+fi
+    if test "x$with_build_python" = xyes; then :
+  with_build_python=python$PACKAGE_VERSION
+fi
+    if test "x$with_build_python" = xno; then :
+  as_fn_error $? "invalid --with-build-python option: expected path, not \"no\"" "$LINENO" 5
+fi
+
     if ! $(command -v "$with_build_python" >/dev/null 2>&1); then
-      as_fn_error $? "invalid or missing build Python binary \"$with_build_python\"" "$LINENO" 5
+      as_fn_error $? "invalid or missing build python binary \"$with_build_python\"" "$LINENO" 5
     fi
     build_python_ver=$($with_build_python -c "import sys; print(f'{sys.version_info.major}.{sys.version_info.minor}')")
     if test "$build_python_ver" != "$PACKAGE_VERSION"; then
       as_fn_error $? "\"$with_build_python\" has incompatible version $build_python_ver (expected: $PACKAGE_VERSION)" "$LINENO" 5
     fi
         ac_cv_prog_PYTHON_FOR_REGEN=$with_build_python
     PYTHON_FOR_BUILD='_PYTHON_PROJECT_BASE=$(abs_builddir) _PYTHON_HOST_PLATFORM=$(_PYTHON_HOST_PLATFORM) PYTHONPATH=$(shell test -f pybuilddir.txt && echo $(abs_builddir)/`cat pybuilddir.txt`:)$(srcdir)/Lib _PYTHON_SYSCONFIGDATA_NAME=_sysconfigdata_$(ABIFLAGS)_$(MACHDEP)_$(MULTIARCH) '$with_build_python
-    { $as_echo "$as_me:${as_lineno-$LINENO}: result: $PYTHON_FOR_BUILD" >&5
-$as_echo "$PYTHON_FOR_BUILD" >&6; }
+    { $as_echo "$as_me:${as_lineno-$LINENO}: result: $with_build_python" >&5
+$as_echo "$with_build_python" >&6; }
 
 else
 

configure.ac

@@ -104,7 +104,7 @@ dnl cross-compiling needs a freeze_module binary for build platform
 AC_ARG_WITH(
   [freeze-module],
   [AS_HELP_STRING([--with-freeze-module=Programs/_freeze_module],
-                  [path to _freeze_module binary for cross compiling (default: self-hosted Programs/_freeze_module binary)])],
+                  [path to _freeze_module binary for cross compiling])],
   [
     AC_MSG_CHECKING([for --with-freeze-module])
     AS_VAR_IF([cross_compiling], [no], AC_MSG_ERROR([--with-freeze-module only applies to cross compiling]))
@@ -127,14 +127,15 @@ AC_SUBST([FREEZE_MODULE])
 
 AC_ARG_WITH(
   [build-python],
-  [AS_HELP_STRING([--with-build-python],
-                  [path to build python binary for cross compiling (default: self-hosted ./python binary)])],
+  [AS_HELP_STRING([--with-build-python=python]PYTHON_VERSION,
+                  [path to build python binary for cross compiling (default: python]PYTHON_VERSION[)])],
   [
     AC_MSG_CHECKING([for --with-build-python])
+
     AS_VAR_IF([cross_compiling], [no], AC_MSG_ERROR([--with-build-python only applies to cross compiling]))
-    if test "$with_build_python" = yes -o "$with_build_python" = no; then
-      AC_MSG_ERROR([invalid -with-build-python option: expected path, not "$with_build_python"])
-    fi
+    AS_VAR_IF([with_build_python], [yes], [with_build_python=python$PACKAGE_VERSION])
+    AS_VAR_IF([with_build_python], [no], [AC_MSG_ERROR([invalid --with-build-python option: expected path, not "no"])])
+
     if ! $(command -v "$with_build_python" >/dev/null 2>&1); then
       AC_MSG_ERROR([invalid or missing build python binary "$with_build_python"])
     fi