Add unit test for argvsplit

Makefile.am

@@ -72,5 +72,10 @@ noinst_HEADERS   = getopt_long.h
 
 dist_doc_DATA = README.md AUTHORS
 
-check: pkgconf
+EXTRA_PROGRAMS = unit_tests
+unit_tests_SOURCES = libpkgconf/tests/argvsplit-test.c
+unit_tests_LDADD   = libpkgconf.la
+
+check: pkgconf unit_tests
+	./unit_tests
 	$(SHELL) tests/run.sh ./pkgconf

libpkgconf/tests/argvsplit-test.c

@@ -0,0 +1,34 @@
+#include <stdio.h>
+#include <assert.h>
+
+#include "../libpkgconf.h"
+
+void test_simple()
+{
+	int argc;
+	char **argv;
+
+	pkgconf_argv_split("A B", &argc, &argv);
+	assert(argc == 2);
+	assert(!strcmp(argv[0], "A"));
+	assert(!strcmp(argv[1], "B"));
+	pkgconf_argv_free(argv);
+}
+
+void test_escaped()
+{
+	int argc;
+	char **argv;
+
+	pkgconf_argv_split("A\\ B", &argc, &argv);
+	assert(argc == 1);
+	assert(!strcmp(argv[0], "A\\ B"));
+	pkgconf_argv_free(argv);
+}
+
+int main(int argc, char **argv)
+{
+	(void) argc; (void) argv;
+	test_simple();
+	test_escaped();
+}