abuild: allow circular makedepends

Some packages like gcc-gnat needs bootstrapping. We need to allow
circular makedepends so we can specify gcc-gnat as makedepends for gcc.

abuild.in

@@ -1536,16 +1536,19 @@ builddeps() {
 
 	# add depends unless it is a subpackage or package itself
 	if cross_compiling && [ -n "$makedepends_build" -o -n "$makedepends_host" ]; then
-		for i in $BUILD_BASE $makedepends_build; do
+		builddeps="$makedepends_build"
+		for i in $BUILD_BASE; do
 			[ "$pkgname" = "${i%%[<>=]*}" ] && continue
 			subpackages_has ${i%%[<>=]*} || builddeps="$builddeps $i"
 		done
-		for i in $depends $makedepends_host; do
+		hostdeps="$makedepends_host"
+		for i in $depends; do
 			[ "$pkgname" = "${i%%[<>=]*}" ] && continue
 			subpackages_has ${i%%[<>=]*} || hostdeps="$hostdeps $i"
 		done
 	else
-		for i in $BUILD_BASE $depends $makedepends; do
+		builddeps="$makedepends"
+		for i in $BUILD_BASE $depends; do
 			[ "$pkgname" = "${i%%[<>=]*}" ] && continue
 			subpackages_has ${i%%[<>=]*} || builddeps="$builddeps $i"
 		done