Append architecture information to 'installed' elements in .BUILDINFO

Adding the architecture to the 'installed' elements of the .BUILDINFO
file makes it easier to retrieve the packages needed to reconstruct
the build environment.
Signed-off-by: Robin Broda <robin@broda.me>
Signed-off-by: Allan McRae <allan@archlinux.org>

doc/BUILDINFO.5.txt

@@ -61,7 +61,7 @@ BUILDINFO file format.
 
 *installed (array)*::
 	The installed packages at build time including the version information of
-	the package. Formatted as "$pkgname-$pkgver-$pkgrel".
+	the package. Formatted as "$pkgname-$pkgver-$pkgrel-$pkgarch".
 
 See Also
 --------

scripts/makepkg.sh.in

@@ -699,8 +699,15 @@ write_buildinfo() {
 	write_kv_pair "buildenv" "${BUILDENV[@]}"
 	write_kv_pair "options" "${OPTIONS[@]}"
 
-	local pkglist=($(run_pacman -Q | sed "s# #-#"))
-	write_kv_pair "installed" "${pkglist[@]}"
+	local pkglist=($(run_pacman -Qq))
+	local pkginfos="$(LC_ALL=C run_pacman -Qi ${pkglist[@]})"
+	local pkginfos_parsed=($(awk -F': ' '\
+		/^Name .*/ {printf $2} \
+		/^Version .*/ {printf "-"$2} \
+		/^Architecture .*/ {print "-"$2} \
+		' <<< "${pkginfos}"))
+
+	write_kv_pair "installed" "${pkginfos_parsed[@]}"
 }
 
 # build a sorted NUL-separated list of the full contents of the current