Add buffered get_env variants to os2

core/os/os2/env_wasi.odin

@@ -67,7 +67,7 @@ delete_string_if_not_original :: proc(str: string) {
 }
 
 @(require_results)
-_lookup_env :: proc(key: string, allocator: runtime.Allocator) -> (value: string, found: bool) {
+_lookup_env_alloc :: proc(key: string, allocator: runtime.Allocator) -> (value: string, found: bool) {
 	if err := build_env(); err != nil {
 		return
 	}
@@ -79,6 +79,34 @@ _lookup_env :: proc(key: string, allocator: runtime.Allocator) -> (value: string
 	return
 }
 
+_lookup_env_buf :: proc(buf: []u8, key: string) -> (value: string, error: Error) {
+	if key == "" {
+		return
+	}
+
+	if len(key) + 1 > len(buf) {
+		return "", .Buffer_Full
+	} else {
+		copy(buf, key)
+	}
+
+	sync.shared_guard(&g_env_mutex)
+
+	val, ok := g_env[key]
+
+	if !ok {
+		return "", .Env_Var_Not_Found
+	} else {
+		if len(val) > len(buf) {
+			return "", .Buffer_Full
+		} else {
+			copy(buf, val)
+			return string(buf[:len(val)]), nil
+		}
+	}
+}
+_lookup_env :: proc{_lookup_env_alloc, _lookup_env_buf}
+
 @(require_results)
 _set_env :: proc(key, value: string) -> (err: Error) {
 	build_env() or_return