tree-wide: do not use "re" with fmemopen

The man page says nothing about "e". Glibc clearly accepts it without fuss, but
it is meaningless for a memory object (and probably doesn't work). This use is
not portable, so let's avoid it.

src/fuzz/fuzz.h

@@ -14,7 +14,7 @@ static inline FILE* data_to_file(const uint8_t *data, size_t size) {
         if (size == 0)
                 return fopen("/dev/null", "re");
         else
-                return fmemopen_unlocked((char*) data, size, "re");
+                return fmemopen_unlocked((char*) data, size, "r");
 }
 
 /* Check if we are within the specified size range.