implement user mode catchable exceptions, refactor system status codes to use NTLSTATUS_ prefix, update build scripts to use shared literal macros for linker arguments, update named queue lifetime cleanup to include KeNamedQueueUnpublishHandle.

code/user/runtime/posix_start.c

@@ -1,13 +1,22 @@
 // POSIX process startup. This file owns process-local POSIX personality initialization before main runs.
 
+#include <stdint.h>
+#include <ntlite/exception.h>
+#include <ntlite/syscall.h>
+
 extern int main(void);
 extern void exit(int status);
 extern void PosixFdInit(void);
 
 // Initializes POSIX process state and exits with main's return value.
 void PosixStart(void) {
+    uint32_t status = NtlInitializeExceptionRuntime();
+    if (status != NTLSTATUS_SUCCESS) {
+        for (;;) SysExitProcess((int32_t)status);
+    }
+
     PosixFdInit();
-    int status = main();
-    exit(status);
+    int exitCode = main();
+    exit(exitCode);
     for (;;) {}
 }