user: implement mlibc as the libc, finally.

It's finally done..

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

user/include/mlibc/tests/rtld/soname/libbar.c

@@ -0,0 +1 @@
+char *name() { return "bar"; }

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

@@ -0,0 +1 @@
+char *name(void) { return "foo"; }

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

@@ -0,0 +1,17 @@
+# Create two libraries with the same SONAME.
+bar_soname = '-Wl,-soname=libbar.so'
+
+libfoo = shared_library('foo', 'libfoo.c', link_args: '-Wl,-soname=libbar.so')
+libbar = shared_library('bar', 'libbar.c', link_args: '-Wl,-soname=libbar.so')
+test_depends = [libfoo, libbar]
+
+libfoo_native = shared_library('native-foo', 'libfoo.c',
+	link_args: ['-ldl', '-Wl,-soname=libnative-bar.so'],
+	native: true
+)
+libbar_native = shared_library('native-bar', 'libbar.c',
+	link_args: ['-ldl', '-Wl,-soname=libnative-bar.so'],
+	native: true
+)
+test_native_depends = [libfoo_native, libbar_native]
+

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

@@ -0,0 +1,35 @@
+#include <dlfcn.h>
+#include <stdio.h>
+#include <assert.h>
+#include <string.h>
+
+#ifdef USE_HOST_LIBC
+#define LIBFOO "libnative-foo.so"
+#define LIBBAR "libnative-bar.so"
+#else
+#define LIBFOO "libfoo.so"
+#define LIBBAR "libbar.so"
+#endif
+
+int main() {
+	void *foo = dlopen(LIBFOO, RTLD_NOW);
+	void *bar = dlopen(LIBBAR, RTLD_NOW);
+	assert(foo);
+	assert(bar);
+
+	// Since these libraries have the same SONAME, they should return the same thing.
+	assert(foo == bar);
+
+	char *(*fooSym)(void) = dlsym(foo, "name");
+	char *(*barSym)(void) = dlsym(bar, "name");
+	assert(fooSym && barSym);
+	assert(fooSym() && barSym());
+	printf("foo: name() = \"%s\"\n", fooSym());
+	printf("bar: name() = \"%s\"\n", barSym());
+	assert(!strcmp(fooSym(), barSym()));
+
+	dlclose(foo);
+	dlclose(bar);
+
+	return 0;
+}