Accept RTLD_GLOBAL flag in dlopen function (#1481)

We always resolve symbols in the global scope in AOT linking, so we can
safely accept the `RTLD_GLOBAL` flag in the `dlopen` function.

Author: kateinoigakukun

crates/wit-component/dl/src/lib.rs

@@ -12,6 +12,7 @@ use core::{
 
 const RTLD_LAZY: c_int = 1;
 const RTLD_NOW: c_int = 2;
+const RTLD_GLOBAL: c_int = 256;
 
 const RTLD_NEXT: isize = -1;
 const RTLD_DEFAULT: isize = 0;
@@ -102,7 +103,7 @@ pub unsafe extern "C" fn dlopen(name: *const c_char, flags: c_int) -> *const c_v
         );
     }
 
-    if (flags & !(RTLD_LAZY | RTLD_NOW)) != 0 {
+    if (flags & !(RTLD_LAZY | RTLD_NOW | RTLD_GLOBAL)) != 0 {
         // TODO
         ERROR = c"dlopen flags not yet supported".as_ptr();
         return ptr::null();

crates/wit-component/libdl.so

@@ -178,8 +178,9 @@
           block ;; label = @3
             block ;; label = @4
               local.get 1
-              i32.const 3
-              i32.le_u
+              i32.const -260
+              i32.and
+              i32.eqz
               br_if 0 (;@4;)
               local.get 3
               i32.const 41