user: implement mlibc as the libc, finally.

It's finally done..

Signed-off-by: kaguya <vpshinomiya@protonmail.com>

user/include/mlibc/tests/rtld/symver/test.c

@@ -0,0 +1,39 @@
+#include <assert.h>
+#include <stdio.h>
+#include <dlfcn.h>
+
+#ifdef USE_HOST_LIBC
+#define LIBFOO "libnative-foo.so"
+#else
+#define LIBFOO "libfoo.so"
+#endif
+
+int foo(void);
+
+int main() {
+	int ver = foo();
+	fprintf(stderr, "called foo version %d\n", ver);
+	assert(ver == 3); // version 3 is the default for libfoo.so
+
+	void *libfoo_h = dlopen(LIBFOO, RTLD_GLOBAL | RTLD_NOW);
+	assert(libfoo_h);
+
+	int (*foo1)(void) = dlvsym(libfoo_h, "foo", "FOO_1");
+	assert(foo1);
+
+	int (*foo2)(void) = dlvsym(libfoo_h, "foo", "FOO_2");
+	assert(foo2);
+
+	int (*foo3)(void) = dlvsym(libfoo_h, "foo", "FOO_3");
+	assert(foo3);
+
+	int (*foo_def)(void) = dlsym(libfoo_h, "foo");
+	assert(foo_def);
+
+	assert(foo1() == 1);
+	assert(foo2() == 2);
+	assert(foo3() == 3);
+	assert(foo3 == foo_def);
+
+	return 0;
+}