Fix stack setting after error return. Some fixes to examples.

resources/examples/binarydigits.c3

@@ -0,0 +1,25 @@
+module binarydigits;
+import std::math;
+import libc;
+fn void main()
+{
+    for (int i = 0; i < 20; i++)
+    {
+        String s = bin(i);
+        defer s.destroy();
+        libc::printf("%s\n", s.zstr());
+    }
+}
+
+fn String bin(int x)
+{
+    int bits = 1 + (int)(x == 0 ? 0 : math::log10((double)(x)) / math::log10(2));
+    String str;
+    str.append_repeat('0', bits);
+    for (int i = 0; i < bits; i++)
+    {
+        str.set((usize)(bits - i - 1), x & 1 ? '1' : '0');
+        x >>= 1;
+    }
+    return str;
+}