user: implement mlibc as the libc, finally.

It's finally done..

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

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

@@ -0,0 +1,15 @@
+int foo_v1(void) {
+	return 1;
+}
+
+int foo_v2(void) {
+	return 2;
+}
+
+int foo_v3(void) {
+	return 3;
+}
+
+asm(".symver foo_v1, foo@FOO_1");
+asm(".symver foo_v2, foo@FOO_2");
+asm(".symver foo_v3, foo@@FOO_3"); // default version (due to @@ vs @)

user/include/mlibc/tests/rtld/symver/libfoo.ver

@@ -0,0 +1,14 @@
+FOO_1 {
+	global: foo;
+	local: *;
+};
+
+FOO_2 {
+	global: foo;
+	local: *;
+};
+
+FOO_3 {
+	global: foo;
+	local: *;
+};

user/include/mlibc/tests/rtld/symver/meson.build

@@ -0,0 +1,11 @@
+version_script = meson.current_source_dir() / 'libfoo.ver'
+
+libfoo = shared_library('foo', 'libfoo.c',
+		link_args : ['-Wl,--version-script', version_script])
+test_depends = [libfoo]
+test_link_with = [libfoo]
+
+libfoo_native = shared_library('native-foo', 'libfoo.c', native: true,
+		link_args : ['-Wl,--version-script', version_script])
+test_native_depends = [libfoo_native]
+test_native_link_with = [libfoo_native]

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;
+}