makepkg.conf: allow configuration additions via a subdirectory

Move rust related buildflags to their own configuration file to
provide an example of how other languages could be supported.

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

etc/makepkg.conf.d/rust.conf.in

@@ -0,0 +1,11 @@
+#!/hint/bash
+#
+# @sysconfdir@/makepkg.conf.d/rust.conf
+#
+
+#########################################################################
+# RUST LANGUAGE SUPPORT
+#########################################################################
+#
+#RUSTFLAGS="-C opt-level=2"
+#DEBUG_RUSTFLAGS="-C debuginfo=2"

etc/makepkg.conf.in

@@ -42,13 +42,11 @@ CHOST="@CHOST@"
 #CXXFLAGS="-O2 -pipe"
 #LDFLAGS=""
 #LTOFLAGS="-flto"
-#RUSTFLAGS="-C opt-level=2"
 #-- Make Flags: change this for DistCC/SMP systems
 #MAKEFLAGS="-j2"
 #-- Debugging flags
 #DEBUG_CFLAGS="-g"
 #DEBUG_CXXFLAGS="-g"
-#DEBUG_RUSTFLAGS="-C debuginfo=2"
 
 #########################################################################
 # BUILD ENVIRONMENT

meson.build

@@ -401,6 +401,12 @@ configure_file(
   configuration : substs,
   install_dir : SYSCONFDIR)
 
+configure_file(
+  input : 'etc/makepkg.conf.d/rust.conf.in',
+  output : 'rust.conf',
+  configuration : substs,
+  install_dir : join_paths(SYSCONFDIR, 'makepkg.conf.d/'))
+
 configure_file(
   input : 'etc/pacman.conf.in',
   output : 'pacman.conf',

scripts/libmakepkg/util/config.sh.in

@@ -37,6 +37,11 @@ source_makepkg_config() {
 	# Source the config file; fail if it is not found
 	if [[ -r $MAKEPKG_CONF ]]; then
 		source_safe "$MAKEPKG_CONF"
+		if [[ -d "$MAKEPKG_CONF.d" ]]; then
+			for c in "$MAKEPKG_CONF.d"/*.conf; do
+				source_safe $c
+			done
+		fi
 	else
 		error "$(gettext "%s not found.")" "$MAKEPKG_CONF"
 		plainerr "$(gettext "Aborting...")"