Fix #69 (No way to set globally a custom architecture)

The "architecture" configuration keyword is now available to override
the native machine architecture returned by (uname(2)).

The XBPS_ARCH environment variable still has preference.

tests/xbps/Kyuafile

@@ -8,3 +8,5 @@ include('xbps-create/Kyuafile')
 include('xbps-install/Kyuafile')
 include('xbps-query/Kyuafile')
 include('xbps-rindex/Kyuafile')
+include('xbps-uhelper/Kyuafile')
+

tests/xbps/Makefile

@@ -1,5 +1,5 @@
 -include ../../config.mk
 
-SUBDIRS = common libxbps xbps-checkvers xbps-create xbps-install xbps-query xbps-rindex
+SUBDIRS = common libxbps xbps-checkvers xbps-create xbps-install xbps-query xbps-rindex xbps-uhelper
 
 include ../../mk/subdir.mk

tests/xbps/xbps-uhelper/Kyuafile

@@ -0,0 +1,4 @@
+syntax("kyuafile", 1)
+
+test_suite("xbps-uhelper")
+atf_test_program{name="arch_test"}

tests/xbps/xbps-uhelper/Makefile

@@ -0,0 +1,8 @@
+TOPDIR = ../../..
+-include $(TOPDIR)/config.mk
+
+TESTSHELL = arch_test
+TESTSSUBDIR = xbps/xbps-uhelper
+EXTRA_FILES = Kyuafile
+
+include $(TOPDIR)/mk/test.mk

tests/xbps/xbps-uhelper/arch_test.sh

@@ -0,0 +1,39 @@
+#! /usr/bin/env atf-sh
+# Test that xbps-uhelper arch works as expected.
+
+atf_test_case native
+
+native_head() {
+	atf_set "descr" "xbps-uhelper arch: native test"
+}
+
+native_body() {
+	atf_check_equal $(xbps-uhelper arch) $(uname -m)
+}
+
+atf_test_case env
+
+env_head() {
+	atf_set "descr" "xbps-uhelper arch: envvar override test"
+}
+env_body() {
+	export XBPS_ARCH=foo
+	atf_check_equal $(xbps-uhelper arch) foo
+}
+
+atf_test_case conf
+
+conf_head() {
+	atf_set "descr" "xbps-uhelper arch: configuration override test"
+}
+conf_body() {
+	mkdir -p xbps.d
+	echo "architecture=x86_64-musl" > xbps.d/arch.conf
+	atf_check_equal $(xbps-uhelper -C $PWD/xbps.d arch) x86_64-musl
+}
+
+atf_init_test_cases() {
+	atf_add_test_case native
+	atf_add_test_case env
+	atf_add_test_case conf
+}