Fix os/spawn - os/execute switch.

src/core/os.c

@@ -332,6 +332,25 @@ typedef struct {
     JanetFile *err;
 } JanetProc;
 
+static int janet_proc_gc(void *p, size_t s) {
+    (void) s;
+    JanetProc *proc = (JanetProc *) p;
+#ifdef JANET_WINDOWS
+    if (!(proc->flags & JANET_PROC_CLOSED)) {
+        CloseHandle(proc->pHandle);
+        CloseHandle(proc->tHandle);
+    }
+#else
+    if (!(proc->flags & JANET_PROC_WAITED)) {
+        /* Kill and wait to prevent zombies */
+        kill(proc->pid, SIGKILL);
+        int status;
+        waitpid(proc->pid, &status, 0);
+    }
+#endif
+    return 0;
+}
+
 static int janet_proc_mark(void *p, size_t s) {
     (void) s;
     JanetProc *proc = (JanetProc *)p;
@@ -371,6 +390,9 @@ static Janet os_proc_wait(int32_t argc, Janet *argv) {
 static Janet os_proc_kill(int32_t argc, Janet *argv) {
     janet_arity(argc, 1, 2);
     JanetProc *proc = janet_getabstract(argv, 0, &ProcAT);
+    if (proc->flags & JANET_PROC_WAITED) {
+        janet_panicf("cannot kill process that has already finished");
+    }
 #ifdef JANET_WINDOWS
     if (proc->flags & JANET_PROC_CLOSED) {
         janet_panicf("cannot close process handle that is already closed");
@@ -422,7 +444,7 @@ static int janet_proc_get(void *p, Janet key, Janet *out) {
 
 static const JanetAbstractType ProcAT = {
     "core/process",
-    NULL,
+    janet_proc_gc,
     janet_proc_mark,
     janet_proc_get,
     JANET_ATEND_GET
@@ -608,11 +630,11 @@ static Janet os_execute_impl(int32_t argc, Janet *argv, int is_async) {
 }
 
 static Janet os_execute(int32_t argc, Janet *argv) {
-    return os_execute_impl(argc, argv, 1);
+    return os_execute_impl(argc, argv, 0);
 }
 
 static Janet os_spawn(int32_t argc, Janet *argv) {
-    return os_execute_impl(argc, argv, 0);
+    return os_execute_impl(argc, argv, 1);
 }
 
 static Janet os_shell(int32_t argc, Janet *argv) {