Move os layer to be part of the core

src/core/os/shell/commander/posix/commander_posix.c

@@ -0,0 +1,23 @@
+#include "aliases.h"
+#include "platform.h"
+
+#ifdef WAPP_PLATFORM_POSIX
+
+#include "commander_output.h"
+#include "shell_utils.h"
+#include <stdio.h>
+#include <stdlib.h>
+
+CMDError get_output_status(FILE *fp, i32 *status_out) {
+  *status_out = wapp_shell_utils_pclose(fp);
+
+  if (!WIFEXITED(*status_out)) {
+    return SHELL_ERR_PROC_EXIT_FAIL;
+  }
+
+  *status_out = WEXITSTATUS(*status_out);
+
+  return SHELL_ERR_NO_ERROR;
+}
+
+#endif // !WAPP_PLATFORM_POSIX