Merge #72

Squash commit of:

commit 7762df2
Author: Valdemar Erk <valdemar@erk.dev>
Date:   Thu Jul 21 22:13:33 2022 +0200

    panic with a specific error if allocating the stack fails.

commit 818af63
Author: Valdemar Erk <valdemar@erk.io>
Date:   Sun Jul 10 16:17:51 2022 +0200

    check errno in case of failure of either mprotect or mmap

    Both libc calls will set errno in case of failure so it can be used
    for both OpenBSD and other systems.

Author: Erk-

src/lib.rs

@@ -164,7 +164,8 @@ psm_stack_manipulation! {
                     0
                 );
                 if new_stack == libc::MAP_FAILED {
-                    panic!("unable to allocate stack")
+                    let error = std::io::Error::last_os_error();
+                    panic!("allocating stack failed with: {}", error)
                 }
                 let guard = StackRestoreGuard {
                     new_stack,
@@ -191,8 +192,9 @@ psm_stack_manipulation! {
                     -1
                 };
                 if result == -1 {
+                    let error = std::io::Error::last_os_error();
                     drop(guard);
-                    panic!("unable to set stack permissions")
+                    panic!("setting stack permissions failed with: {}", error)
                 }
                 guard
             }