coreutils: use single binary in symlink method

The symlink method is faster, since there is no shell fork/exec, and
provides extra space savings.

Signed-off-by: Carlos Santos <casantos@datacom.ind.br>
[Thomas: use the symlinks method not only for the merged /usr case,
but also in the non-merged case to be consistent, and therefore adjust
the logic that was moving the shell wrappers to a logic that recreates
the symlinks.]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/coreutils/coreutils.mk

@@ -14,7 +14,7 @@ COREUTILS_LICENSE_FILES = COPYING
 COREUTILS_AUTORECONF = YES
 COREUTILS_GETTEXTIZE = YES
 
-COREUTILS_CONF_OPTS = --disable-rpath --enable-single-binary=shebangs \
+COREUTILS_CONF_OPTS = --disable-rpath --enable-single-binary=symlinks \
 	$(if $(BR2_TOOLCHAIN_USES_MUSL),--with-included-regex)
 COREUTILS_CONF_ENV = ac_cv_c_restrict=no \
 	ac_cv_func_chown_works=yes \
@@ -103,9 +103,10 @@ endif
 
 ifeq ($(BR2_ROOTFS_MERGED_USR),)
 define COREUTILS_CLEANUP_BIN
-	# some things go in root rather than usr
+	# some things go in /bin rather than /usr/bin
 	$(foreach f,$(COREUTILS_BIN_PROGS), \
-		mv -f $(TARGET_DIR)/usr/bin/$(f) $(TARGET_DIR)/bin/$(f)
+		rm -f $(TARGET_DIR)/usr/bin/$(f) && \
+		ln -sf ../usr/bin/coreutils $(TARGET_DIR)/bin/$(f)
 	)
 endef
 COREUTILS_POST_INSTALL_TARGET_HOOKS += COREUTILS_CLEANUP_BIN