libmakepkg: move rust buildenv handling to separate file

This serves as a demonstration for how other languages could drop
in support into libmakepkg.

Signed-off-by: Allan McRae <allan@archlinux.org>

scripts/libmakepkg/buildenv.sh.in

@@ -25,12 +25,13 @@ LIBMAKEPKG_BUILDENV_SH=1
 LIBRARY=${LIBRARY:-'@libmakepkgdir@'}
 
 declare -a buildenv_functions build_options
+buildenv_vars=('CPPFLAGS' 'CFLAGS' 'CXXFLAGS' 'LDFLAGS' 'MAKEFLAGS' 'CHOST')
 
 for lib in "$LIBRARY/buildenv/"*.sh; do
 	source "$lib"
 done
 
-readonly -a buildenv_functions build_options
+readonly -a buildenv_functions buildenv_vars build_options
 
 prepare_buildenv() {
 	for func in ${buildenv_functions[@]}; do
@@ -38,5 +39,5 @@ prepare_buildenv() {
 	done
 
 	# ensure all necessary build variables are exported
-	export CPPFLAGS CFLAGS CXXFLAGS LDFLAGS RUSTFLAGS MAKEFLAGS CHOST
+	export ${buildenv_vars[@]}
 }

scripts/libmakepkg/buildenv/buildflags.sh.in

@@ -30,6 +30,6 @@ buildenv_functions+=('buildenv_buildflags')
 
 buildenv_buildflags() {
 	if check_option "buildflags" "n"; then
-		unset CPPFLAGS CFLAGS DEBUG_CFLAGS CXXFLAGS DEBUG_CXXFLAGS LDFLAGS LTOFLAGS RUSTFLAGS DEBUG_RUSTFLAGS
+		unset ${buildenv_vars[@]}
 	fi
 }

scripts/libmakepkg/buildenv/debugflags.sh.in

@@ -32,9 +32,7 @@ buildenv_debugflags() {
 	if check_option "debug" "y" && ! check_option "buildflags" "n"; then
 		DEBUG_CFLAGS+=" -ffile-prefix-map=$srcdir=${DBGSRCDIR:-/usr/src/debug}/${pkgbase}"
 		DEBUG_CXXFLAGS+=" -ffile-prefix-map=$srcdir=${DBGSRCDIR:-/usr/src/debug}/${pkgbase}"
-		DEBUG_RUSTFLAGS+=" --remap-path-prefix=$srcdir=${DBGSRCDIR:-/usr/src/debug}/${pkgbase}"
 		CFLAGS+=" $DEBUG_CFLAGS"
 		CXXFLAGS+=" $DEBUG_CXXFLAGS"
-		RUSTFLAGS+=" $DEBUG_RUSTFLAGS"
 	fi
 }

scripts/libmakepkg/buildenv/meson.build

@@ -6,6 +6,7 @@ sources = [
   'debugflags.sh.in',
   'lto.sh.in',
   'makeflags.sh.in',
+  'rust.sh.in',
 ]
 
 foreach src : sources

scripts/libmakepkg/buildenv/rust.sh.in

@@ -0,0 +1,36 @@
+#!/usr/bin/bash
+#
+#   rust.sh - Specify flags for building a package with rust
+#
+#   Copyright (c) 2022 Pacman Development Team <pacman-dev@lists.archlinux.org>
+#
+#   This program is free software; you can redistribute it and/or modify
+#   it under the terms of the GNU General Public License as published by
+#   the Free Software Foundation; either version 2 of the License, or
+#   (at your option) any later version.
+#
+#   This program is distributed in the hope that it will be useful,
+#   but WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#   GNU General Public License for more details.
+#
+#   You should have received a copy of the GNU General Public License
+#   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+[[ -n "$LIBMAKEPKG_BUILDENV_RUST_SH" ]] && return
+LIBMAKEPKG_BUILDENV_RUST_SH=1
+
+LIBRARY=${LIBRARY:-'@libmakepkgdir@'}
+
+source "$LIBRARY/util/option.sh"
+
+buildenv_var+=('RUSTFLAGS' 'DEBUG_RUSTFLAGS')
+buildenv_functions+=('buildenv_rust')
+
+buildenv_rust() {
+	if check_option "debug" "y" && ! check_option "buildflags" "n"; then
+		DEBUG_RUSTFLAGS+=" --remap-path-prefix=$srcdir=${DBGSRCDIR:-/usr/src/debug}/${pkgbase}"
+		RUSTFLAGS+=" $DEBUG_RUSTFLAGS"
+	fi
+}

scripts/libmakepkg/lint_config/variable.sh.in

@@ -32,10 +32,10 @@ lint_config_variables() {
 	local array=(DLAGENTS VCSCLIENTS BUILDENV OPTIONS INTEGRITY_CHECK MAN_DIRS
 	             DOC_DIRS PURGE_TARGETS COMPRESSGZ COMPRESSBZ2 COMPRESSXZ
 	             COMPRESSLRZ COMPRESSLZO COMPRESSZ)
-	local string=(CARCH CHOST CPPFLAGS CFLAGS CXXFLAGS RUSTFLAGS LDFLAGS LTOFLAGS
+	local string=(CARCH CHOST CPPFLAGS CFLAGS CXXFLAGS LDFLAGS LTOFLAGS DEBUG_CFLAGS
-	              DEBUG_CFLAGS DEBUG_CXXFLAGS DEBUG_RUSTFLAGS DISTCC_HOSTS BUILDDIR
+	              DEBUG_CXXFLAGS DISTCC_HOSTS BUILDDIR STRIP_BINARIES STRIP_SHARED
-	              STRIP_BINARIES STRIP_SHARED STRIP_STATIC PKGDEST SRCDEST SRCPKGDEST
+	              STRIP_STATIC PKGDEST SRCDEST SRCPKGDEST LOGDEST PACKAGER GPGKEY
-	              LOGDEST PACKAGER GPGKEY PKGEXT SRCEXT)
+	              PKGEXT SRCEXT)
 
 	local i keys ret=0