Fixes for Python cross-compilation, Linux to Linux at least

When not using a system Python, set PYTHON_FOR_BUILD to point to the
python script in the instdir_for_build/program folder. Make sure that
script gets installed by adding it to gb_BUILD_TOOLS_executables and
by adding pyuno to the cross_toolset modules. Make also the
SYSTEM_PYTHON boolean flag visible to the cross-build (in the normal
way, as SYSTEM_PYTHON_FOR_BUILD).

When cross-compiling Python to Linux, pass some ac_cv_* settings that
can't be determined at compile time.

Change-Id: I5224966698dca03df9545f5552671f0dce00b4ca
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/197540
Reviewed-by: Tor Lillqvist <tml@iki.fi>
Tested-by: Jenkins

RepositoryModule_build.mk

@@ -37,6 +37,7 @@ $(eval $(call gb_Module_add_moduledirs,cross_toolset,\
 	officecfg \
 	oovbaapi \
 	pch \
+	$(if $(filter PYTHON,$(BUILD_TYPE_FOR_HOST)),pyuno) \
 	registry \
 	remotebridges \
 	ridljar \

config_host.mk.in

@@ -728,6 +728,7 @@ SYSTEM_PAGEMAKER=@SYSTEM_PAGEMAKER@
 SYSTEM_POPPLER=@SYSTEM_POPPLER@
 SYSTEM_POSTGRESQL=@SYSTEM_POSTGRESQL@
 SYSTEM_PYTHON=@SYSTEM_PYTHON@
+SYSTEM_PYTHON_FOR_BUILD=@SYSTEM_PYTHON_FOR_BUILD@
 SYSTEM_ZXCVBN=@SYSTEM_ZXCVBN@
 SYSTEM_ZXING=@SYSTEM_ZXING@
 SYSTEM_QXP=@SYSTEM_QXP@

configure.ac

@@ -6410,6 +6410,7 @@ if test "$cross_compiling" = "yes"; then
         LIBO_URE_MISC_FOLDER
         OS
         SDKDIRNAME
+        SYSTEM_PYTHON
         SYSTEM_LIBXML
         SYSTEM_LIBXSLT
 "
@@ -6496,6 +6497,7 @@ else
     LIBO_URE_MISC_FOLDER_FOR_BUILD="$LIBO_URE_MISC_FOLDER"
     SDKDIRNAME_FOR_BUILD="$SDKDIRNAME"
     WORKDIR_FOR_BUILD="$WORKDIR"
+    SYSTEM_PYTHON_FOR_BUILD="$SYSTEM_PYTHON"
 fi
 AC_SUBST(OS_FOR_BUILD)
 AC_SUBST(INSTDIR_FOR_BUILD)
@@ -6509,6 +6511,7 @@ AC_SUBST(WORKDIR_FOR_BUILD)
 AC_SUBST(CC_FOR_BUILD)
 AC_SUBST(CXX_FOR_BUILD)
 AC_SUBST(CPPU_ENV_FOR_BUILD)
+AC_SUBST(SYSTEM_PYTHON_FOR_BUILD)
 
 dnl ===================================================================
 dnl Check for lockfile deps
@@ -10526,7 +10529,11 @@ if test "$build_os" != "cygwin" -a "$enable_python" != fully-internal; then
         # Clean PYTHON_VERSION checked below if cross-compiling
         PYTHON_VERSION=""
         if test "$PYTHON" != ":"; then
-            PYTHON_FOR_BUILD=$PYTHON
+            if test -n "$CROSS_COMPILING" -a -z "$SYSTEM_PYTHON_FOR_BUILD"; then
+                PYTHON_FOR_BUILD="$INSTDIR_FOR_BUILD/$LIBO_BIN_FOLDER_FOR_BUILD/python"
+            else
+                PYTHON_FOR_BUILD=$PYTHON
+            fi
         fi
     fi
 fi

external/python3/ExternalProject_python3.mk

@@ -94,8 +94,16 @@ $(call gb_ExternalProject_get_state_target,python3,build) :
 				ac_cv_func_clock_gettime=no \
 			) \
 		) \
+		$(if $(CROSS_COMPILING), \
+			$(if $(filter LINUX,$(OS)), \
+				ac_cv_buggy_getaddrinfo=no \
+				ac_cv_file__dev_ptmx=yes \
+				ac_cv_file__dev_ptc=yes \
+			) \
+		) \
 		$(gb_RUN_CONFIGURE) ./configure \
 		$(gb_CONFIGURE_PLATFORMS) \
+		$(if $(CROSS_COMPILING),--with-build-python="$(PYTHON_FOR_BUILD)") \
 		$(if $(ENABLE_VALGRIND),--with-valgrind) \
 		$(if $(ENABLE_DBGUTIL),--with-pydebug) \
 		--prefix=/python-inst \

solenv/gbuild/extensions/pre_BuildTools.mk

@@ -27,6 +27,7 @@ gb_BUILD_TOOLS_executables = \
     $(call gb_CondExeLockfile,lockfile) \
 		makedepend \
 		propex \
+		$(if $(filter PYTHON,$(BUILD_TYPE_FOR_HOST)),python) \
 		saxparser \
 		svidl \
 		treex \