python3: bundle libffi for GNU/Linux builds

CPython commit f40d4ddff3c800b3c956a5e8820aabe3aa87cddd "Closes #27979:
Remove bundled copy of libffi" causes a bit of a problem because it
turns out that libffi isn't all that stable; there's libffi.so.5 on
CentOS 6, libffi.so.6 on CentOS 7 and libffi.so.7 on
lo_daily_update_gandalf tinderbox.

So we have to bundle it in LO; it's only used on GNU/Linux currently.

CPython commit 32119e10b792ad7ee4e5f951a2d89ddbaf111cc5 "bpo-35947:
Update Windows to the current version of libffi (GH-11797)" also removes
the libffi for MSVC, so in a future python upgrade we will have to build
libffi for MSVC too.

The libffi fork for MacOSX is still in CPython git master.

(regression from b10be5d48433076f0b7238d818020f708553e114)

Change-Id: Ibc20cf8cd3614cf9941b6970662bd930496776b2
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/86493
Tested-by: Jenkins
Reviewed-by: Michael Stahl <michael.stahl@cib.de>
(cherry picked from commit 79084665f0e351a3f83fdee88071919f05ec9cc3)
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/86500
Reviewed-by: Caolán McNamara <caolanm@redhat.com>

7 files changed, 86 insertions, 2 deletions

diff --git a/external/Module_external.mk b/external/Module_external.mk
index 10ed2a6e54db..baf7215b2b70 100644
--- a/external/Module_external.mk
+++ b/external/Module_external.mk
@@ -57,6 +57,7 @@ $(eval $(call gb_Module_add_moduledirs,external,\
 	$(call gb_Helper_optional,LIBATOMIC_OPS,libatomic_ops) \
 	$(call gb_Helper_optional,LIBEOT,libeot) \
 	$(call gb_Helper_optional,LIBEXTTEXTCAT,libexttextcat) \
+	$(call gb_Helper_optional,LIBFFI,libffi) \
 	$(call gb_Helper_optional,LIBGPGERROR,libgpg-error) \
 	$(call gb_Helper_optional,LIBLANGTAG,liblangtag) \
 	$(call gb_Helper_optional,LIBNUMBERTEXT,libnumbertext) \
diff --git a/external/libffi/ExternalProject_libffi.mk b/external/libffi/ExternalProject_libffi.mk
new file mode 100644
index 000000000000..bdf8fe61eb76
--- /dev/null
+++ b/external/libffi/ExternalProject_libffi.mk
@@ -0,0 +1,33 @@
+# -*- Mode: makefile-gmake; tab-width: 4; indent-tabs-mode: t -*-
+#
+# This file is part of the LibreOffice project.
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+#
+
+$(eval $(call gb_ExternalProject_ExternalProject,libffi))
+
+$(eval $(call gb_ExternalProject_register_targets,libffi,\
+	build \
+))
+
+# set prefix so that it ends up in libffi.pc so that pkg-config in python3 works
+
+$(call gb_ExternalProject_get_state_target,libffi,build):
+	$(call gb_ExternalProject_run,build,\
+		./configure \
+			--enable-option-checking=fatal \
+			$(if $(CROSS_COMPILING),--build=$(BUILD_PLATFORM) --host=$(HOST_PLATFORM)) \
+			--enable-static \
+			--disable-shared \
+			--with-pic \
+			--enable-portable-binary \
+			CC="$(CC) $(if $(filter LINUX,$(OS)),-fvisibility=hidden)" \
+			--prefix=$(call gb_UnpackedTarball_get_dir,libffi)/$(HOST_PLATFORM) \
+			--disable-docs \
+		&& $(MAKE) \
+	)
+
+# vim: set noet sw=4 ts=4:
diff --git a/external/libffi/Makefile b/external/libffi/Makefile
new file mode 100644
index 000000000000..e4968cf85fb6
--- /dev/null
+++ b/external/libffi/Makefile
@@ -0,0 +1,7 @@
+# -*- Mode: makefile-gmake; tab-width: 4; indent-tabs-mode: t -*-
+
+module_directory:=$(dir $(realpath $(firstword $(MAKEFILE_LIST))))
+
+include $(module_directory)/../../solenv/gbuild/partial_build.mk
+
+# vim: set noet sw=4 ts=4:
diff --git a/external/libffi/Module_libffi.mk b/external/libffi/Module_libffi.mk
new file mode 100644
index 000000000000..739fd4197000
--- /dev/null
+++ b/external/libffi/Module_libffi.mk
@@ -0,0 +1,17 @@
+# -*- Mode: makefile-gmake; tab-width: 4; indent-tabs-mode: t -*-
+#
+# This file is part of the LibreOffice project.
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+#
+
+$(eval $(call gb_Module_Module,libffi))
+
+$(eval $(call gb_Module_add_targets,libffi,\
+	UnpackedTarball_libffi \
+	ExternalProject_libffi \
+))
+
+# vim: set noet sw=4 ts=4:
diff --git a/external/libffi/README b/external/libffi/README
new file mode 100644
index 000000000000..cdf7fa937bc8
--- /dev/null
+++ b/external/libffi/README
@@ -0,0 +1,3 @@
+libffi is required to build CPython's ctypes module
+
+https://sourceware.org/libffi/
diff --git a/external/libffi/UnpackedTarball_libffi.mk b/external/libffi/UnpackedTarball_libffi.mk
new file mode 100644
index 000000000000..5d0582329ac5
--- /dev/null
+++ b/external/libffi/UnpackedTarball_libffi.mk
@@ -0,0 +1,14 @@
+# -*- Mode: makefile-gmake; tab-width: 4; indent-tabs-mode: t -*-
+#
+# This file is part of the LibreOffice project.
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+#
+
+$(eval $(call gb_UnpackedTarball_UnpackedTarball,libffi))
+
+$(eval $(call gb_UnpackedTarball_set_tarball,libffi,$(LIBFFI_TARBALL)))
+
+# vim: set noet sw=4 ts=4:
diff --git a/external/python3/ExternalProject_python3.mk b/external/python3/ExternalProject_python3.mk
index 5350f9e4c5d9..6c958431cd97 100644
--- a/external/python3/ExternalProject_python3.mk
+++ b/external/python3/ExternalProject_python3.mk
@@ -11,6 +11,7 @@ $(eval $(call gb_ExternalProject_ExternalProject,python3))
 
 $(eval $(call gb_ExternalProject_use_externals,python3,\
 	expat \
+	$(if $(filter LINUX,$(OS)),libffi) \
 	openssl \
 	zlib \
 ))
@@ -52,8 +53,12 @@ else
 # OPENSSL_INCLUDES OPENSSL_LDFLAGS OPENSSL_LIBS cannot be set via commandline!
 # use --with-openssl instead, which requires include/ and lib/ subdirs.
 
-# TODO: libffi has different SONAME on CentOS 6 vs. 7, so we better use
-# --without-system-ffi. However, that doesn't actually do anything on Linux :(
+# libffi is not all that stable, with 3 different SONAMEs currently, so we
+# have to bundle it; --without-system-ffi does not work any more on Linux.
+# Unfortuantely (as of 3.7) pkg-config is used to locate libffi so we do some
+# hacks to find the libffi.pc in workdir by overriding PKG_CONFIG_LIBDIR.
+# Also, pkg-config is only used to find the headers, the libdir needs to be
+# passed extra.
 
 # create a symlink "LO_lib" because the .so are in a directory with platform
 # specific name like build/lib.linux-x86_64-3.3
@@ -91,6 +96,9 @@ $(call gb_ExternalProject_get_state_target,python3,build) :
 		$(if $(SYSTEM_OPENSSL)$(DISABLE_OPENSSL),,\
 			--with-openssl=$(call gb_UnpackedTarball_get_dir,openssl) \
 		) \
+		$(if $(filter LINUX,$(OS)), \
+			PKG_CONFIG_LIBDIR="$(call gb_UnpackedTarball_get_dir,libffi)/$(HOST_PLATFORM)$${PKG_CONFIG_LIBDIR:+:$$PKG_CONFIG_LIBDIR}" \
+		) \
 		CC="$(strip $(CC) \
 			$(if $(SYSTEM_EXPAT),,-I$(call gb_UnpackedTarball_get_dir,expat)/lib) \
 			$(if $(SYSBASE), -I$(SYSBASE)/usr/include) \
@@ -98,6 +106,7 @@ $(call gb_ExternalProject_get_state_target,python3,build) :
 		$(if $(python3_cflags),CFLAGS='$(python3_cflags)') \
 		$(if $(filter -fsanitize=%,$(CC)),LINKCC="$(CXX) -pthread") \
 		LDFLAGS="$(strip $(LDFLAGS) \
+			$(if $(filter LINUX,$(OS)),-L$(call gb_UnpackedTarball_get_dir,libffi)/$(HOST_PLATFORM)/.libs) \
 			$(if $(SYSTEM_EXPAT),,-L$(gb_StaticLibrary_WORKDIR)) \
 			$(if $(SYSTEM_ZLIB),,-L$(gb_StaticLibrary_WORKDIR)) \
 			$(if $(SYSBASE), -L$(SYSBASE)/usr/lib) \