internal/rosa/gnu: build single-binary coreutils

This enables more fine-grained toybox replacements.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/rosa/gnu.go

@@ -269,10 +269,14 @@ test_disable() { chmod +w "$2" && echo "$1" > "$2"; }
 test_disable '#!/bin/sh' gnulib-tests/test-c32ispunct.sh
 test_disable '#!/bin/sh' tests/split/line-bytes.sh
 test_disable '#!/bin/sh' tests/dd/no-allocate.sh
+test_disable '#!/bin/sh' tests/env/env.sh
 test_disable 'int main(){return 0;}' gnulib-tests/test-chown.c
 test_disable 'int main(){return 0;}' gnulib-tests/test-fchownat.c
 test_disable 'int main(){return 0;}' gnulib-tests/test-lchown.c
 `,
+		Configure: [][2]string{
+			{"enable-single-binary", "symlinks"},
+		},
 		Flag: TEarly,
 	},
 		t.Load(Perl),