[gentoo-dev] [PATCH] Support wrapping headers for multilib ABIs.

[Michał Górny]

This time using a template like Alexis suggested. I've only added
the ABIs currently supported by multilib-build. Feel free to provide me
with a more complete one.
---
 gx86/eclass/autotools-multilib.eclass | 93 +++++++++++++++++++++++++++++++++++
 1 file changed, 93 insertions(+)

diff --git a/gx86/eclass/autotools-multilib.eclass b/gx86/eclass/autotools-multilib.eclass
index d7372b0..ccbaac6 100644
--- a/gx86/eclass/autotools-multilib.eclass
+++ b/gx86/eclass/autotools-multilib.eclass
@@ -33,6 +33,28 @@ inherit autotools-utils multilib-build
 
 EXPORT_FUNCTIONS src_prepare src_configure src_compile src_test src_install
 
+# @ECLASS-VARIABLE: MULTILIB_WRAPPED_HEADERS
+# @DESCRIPTION:
+# A list of headers to wrap for multilib support. The listed headers
+# will be moved to a non-standard location and replace with a file
+# including them conditionally to current ABI.
+#
+# This variable has to be a bash array. Paths shall be relative to
+# installation root (${ED}), and name regular files. Recursive wrapping
+# is not supported.
+#
+# Please note that header wrapping is *discouraged*. It is preferred to
+# install all headers in a subdirectory of libdir and use pkg-config to
+# locate the headers. Some C preprocessors will not work with wrapped
+# headers.
+#
+# Example:
+# @CODE
+# MULTILIB_WRAPPED_HEADERS=(
+#	/usr/include/foobar/config.h
+# )
+# @CODE
+
 autotools-multilib_src_prepare() {
 	autotools-utils_src_prepare "${@}"
 }
@@ -49,13 +71,84 @@ autotools-multilib_src_test() {
 	multilib_foreach_abi autotools-utils_src_test "${@}"
 }
 
+_autotools-multilib_wrap_headers() {
+	debug-print-function ${FUNCNAME} "$@"
+	local f
+
+	for f in "${MULTILIB_WRAPPED_HEADERS[@]}"; do
+		# drop leading slash if it's there
+		f=${f#/}
+
+		if [[ ${f} != usr/include/* ]]; then
+			die "Wrapping headers outside of /usr/include is not supported at the moment."
+		fi
+		# and then usr/include
+		f=${f#usr/include/}
+
+		local dir=${f%/*}
+
+		# $CHOST shall be set by multilib_toolchain_setup
+		dodir "/tmp/multilib-include/${CHOST}/${dir}"
+		mv "${ED}/usr/include/${f}" "${ED}/tmp/multilib-include/${CHOST}/${dir}/" || die
+
+		if [[ ! -f ${ED}/tmp/multilib-include/${f} ]]; then
+			dodir "/tmp/multilib-include/${dir}"
+			# a generic template
+			cat > "${ED}/tmp/multilib-include/${f}" <<_EOF_ || die
+/* This file is auto-generated by autotools-multilib.eclass
+ * as a multilib-friendly wrapper. For the original content,
+ * please see the files that are #included below.
+ */
+
+#if defined(__x86_64__) /* amd64 */
+#	if defined(__ILP32__) /* x32 ABI */
+#		error "abi_x86_x32 not supported by the package."
+#	else /* 64-bit ABI */
+#		error "abi_x86_64 not supported by the package."
+#	endif
+#elif defined(__i386__) /* plain x86 */
+#	error "abi_x86_32 not supported by the package."
+#else
+#	error "No ABI matched, please report a bug to bugs.gentoo.org"
+#endif
+_EOF_
+		fi
+
+		# XXX: get abi_* directly
+		local abi_flag
+		case "${ABI}" in
+			amd64)
+				abi_flag=abi_x86_64;;
+			x86)
+				abi_flag=abi_x86_32;;
+			x32)
+				abi_flag=abi_x86_x32;;
+			*)
+				die "Header wrapping for ${ABI} not supported yet";;
+		esac
+
+		# Note: match a space afterwards to avoid collision potential.
+		sed -e "/${abi_flag} /s&error.*&include <${CHOST}/${f}>&" \
+			-i "${ED}/tmp/multilib-include/${f}" || die
+	done
+}
+
 autotools-multilib_src_install() {
 	autotools-multilib_secure_install() {
 		autotools-utils_src_install "${@}"
 
+		_autotools-multilib_wrap_headers
 		# Make sure all headers are the same for each ABI.
 		multilib_check_headers
 	}
 
 	multilib_foreach_abi autotools-multilib_secure_install "${@}"
+
+	# merge the wrapped headers
+	if [[ -d "${ED}"/tmp/multilib-include ]]; then
+		multibuild_merge_root \
+			"${ED}"/tmp/multilib-include "${ED}"/usr/include
+		# it can fail if something else uses /tmp
+		rmdir "${ED}"/tmp &>/dev/null
+	fi
 }
-- 
1.8.1.5