diff --git a/mlibc/libc-mes+tcc.c b/mlibc/libc-mes+tcc.c
index e075768f..24657e96 100644
--- a/mlibc/libc-mes+tcc.c
+++ b/mlibc/libc-mes+tcc.c
@@ -335,8 +335,27 @@ time_t time (time_t *tloc)
 int
 vsnprintf (char *str, size_t size, char const *format, va_list ap)
 {
-  eputs ("vsnprintf stub\n");
-  return 0;
+  char const *p = format;
+  while (*p)
+    if (*p != '%')
+      *str++ = *p++;
+    else
+      {
+        p++;
+        char c = *p;
+        switch (c)
+          {
+          case '%': {*str++ = *p; break;}
+          case 'c': {char c; c = va_arg (ap, char); *str++=c; break;}
+          case 'd': {int d; d = va_arg (ap, int); strcpy (str, itoa (d)); break;}
+          case 's': {char *s; s = va_arg (ap, char *); strcpy (str, s); break;}
+          default: {*str++ = *p; break;}
+          }
+        p++;
+      }
+  va_end (ap);
+  *str = 0;
+  return strlen (str);
 }
 
 void *
diff --git a/module/language/c99/compiler.mes b/module/language/c99/compiler.mes
index 36cd72cd..1d14824b 100644
--- a/module/language/c99/compiler.mes
+++ b/module/language/c99/compiler.mes
@@ -1283,6 +1283,8 @@
 (define (ast-type->type info o)
   (pmatch o
     ((p-expr ,expr) (ast-type->type info (p-expr->type info o)))
+    ((pre-inc ,expr) (ast-type->type info expr))
+    ((post-inc ,expr) (ast-type->type info expr))
     ((decl-spec-list ,type-spec)
      (ast-type->type info type-spec))
     ((decl-spec-list (type-qual ,qual) (type-spec (fixed-type ,type)))