libxbps: pkg remove: never remove base symlinks in the root directory.

The /bin, /sbin, /lib, /lib32, /lib64, /var/run symlinks should never be removed
in Void, so be safe and ignore the removal of them.

Added another test to the testsuite to verify its correctness.

tests/xbps/libxbps/common/Kyuafile

@@ -12,5 +12,6 @@ atf_test_program{name="issue6_test"}
 atf_test_program{name="issue18_test"}
 atf_test_program{name="issue20_test"}
 atf_test_program{name="conf_files_test"}
+atf_test_program{name="remove_test"}
 include('find_pkg_orphans/Kyuafile')
 include('pkgdb/Kyuafile')

tests/xbps/libxbps/shell/Makefile

@@ -1,7 +1,7 @@
 TOPDIR = ../../../..
 -include $(TOPDIR)/config.mk
 
-TESTSHELL = conf_files_test issue6_test issue18_test issue20_test
+TESTSHELL = conf_files_test issue6_test issue18_test issue20_test remove_test
 
 include ../Makefile.inc
 include $(TOPDIR)/mk/test.mk

tests/xbps/libxbps/shell/remove_test.sh

@@ -0,0 +1,37 @@
+#! /usr/bin/env atf-sh
+
+# 1st test: make sure that base symlinks on rootdir are not removed.
+atf_test_case keep_base_symlinks
+
+keep_base_symlinks_head() {
+	atf_set "descr" "Tests for package removal: keep base symlinks test"
+}
+
+keep_base_symlinks_body() {
+	mkdir -p root/usr/bin
+	ln -sfr root/usr/bin root/bin
+
+	mkdir some_repo
+	mkdir -p pkg_A/usr/bin pkg_A/bin
+	touch -f pkg_A/usr/bin/foo
+	cd some_repo
+	xbps-create -A noarch -n foo-1.0_1 -s "foo pkg" ../pkg_A
+	atf_check_equal $? 0
+	xbps-rindex -a *.xbps
+	atf_check_equal $? 0
+	cd ..
+	xbps-install -r root --repository=some_repo -y foo
+	atf_check_equal $? 0
+	xbps-remove -r root -y foo
+	atf_check_equal $? 0
+	if [ -h root/bin ]; then
+		rv=0
+	else
+		rv=1
+	fi
+	atf_check_equal $rv 0
+}
+
+atf_init_test_cases() {
+	atf_add_test_case keep_base_symlinks
+}