When exec fails show the command, why it failed, and if it failed because the...

When exec fails show the command, why it failed, and if it failed because the file wasn't found, show the PATH that was searched

sources/shell_launcher.c

@@ -7,6 +7,7 @@
 #include "shell_launcher.h"
 #include <err.h>
 #include <errno.h>
+#include <paths.h>
 #include <sys/msg.h>
 #include <stdlib.h>
 #include <string.h>
@@ -66,6 +67,11 @@ static void ExecChild(int argc, char *const *argv) {
     // TODO: The first arg should be just the last path component.
     execvp(argv[0], argv);
+    int error = errno;
+    printf("Failed to exec %s: %s\n", argv[0], strerror(errno));
+    if (error == ENOENT) {
+        printf("PATH=%s\n", getenv("PATH") ?: _PATH_DEFPATH);
+    }
 }
 static void CreateProcessGroup() {