Try to map to General_Error where possible

core/os/env_windows.odin

@@ -7,6 +7,7 @@ import "base:runtime"
 // If the variable is found in the environment the value (which can be empty) is returned and the boolean is true
 // Otherwise the returned value will be empty and the boolean will be false
 // NOTE: the value will be allocated with the supplied allocator
+@(require_results)
 lookup_env :: proc(key: string, allocator := context.allocator) -> (value: string, found: bool) {
 	if key == "" {
 		return
@@ -33,6 +34,7 @@ lookup_env :: proc(key: string, allocator := context.allocator) -> (value: strin
 // It returns the value, which will be empty if the variable is not present
 // To distinguish between an empty value and an unset value, use lookup_env
 // NOTE: the value will be allocated with the supplied allocator
+@(require_results)
 get_env :: proc(key: string, allocator := context.allocator) -> (value: string) {
 	value, _ = lookup_env(key, allocator)
 	return
@@ -60,6 +62,7 @@ unset_env :: proc(key: string) -> Errno {
 
 // environ returns a copy of strings representing the environment, in the form "key=value"
 // NOTE: the slice of strings and the strings with be allocated using the supplied allocator
+@(require_results)
 environ :: proc(allocator := context.allocator) -> []string {
 	envs := ([^]win32.WCHAR)(win32.GetEnvironmentStringsW())
 	if envs == nil {