fix: inherit process environment and untrack libc objects

programs/man/syscalls.2

@@ -39,7 +39,8 @@
         int montauk::getpid();
 
 .B SYS_SPAWN (20)
-    Spawn a new process from an ELF binary on the VFS.
+    Spawn a new process from an ELF binary on the VFS. The child inherits
+    a snapshot of the caller's environment.
         int montauk::spawn(const char* path, const char* args = nullptr);
 
 .B SYS_WAITPID (23)
@@ -50,6 +51,11 @@
     Get the argument string passed to this process at spawn time.
         int montauk::getargs(char* buf, uint64_t maxLen);
 
+.B SYS_GETENVIRON (171), SYS_SETENVIRON (172), SYS_SPAWN_ENV (173)
+    Libc process-environment transport. Environment data is encoded as
+    consecutive NAME=VALUE strings with a final empty string. Applications
+    normally use getenv(3), setenv(3), environ, and posix_spawn(3).
+
 .B SYS_PROCLIST (61)
     List running processes (pid, parent, state, name, heap usage,
     accumulated CPU time).