Avoiding tempnam (in favor of mkstemp)

[Gerald Pfeifer]

We have had some (security-relevant) warning regressions for the following
two programs in tools:

winegcc.o: In function `get_temp_file':
    /test/wine/tools/winegcc.c:119: warning: tempnam()
    possibly used unsafely; consider using mkstemp()
  winewrap.o: In function `main':
    /test/wine/tools/winewrap.c(.text+0x7fe): warning:
    tempnam() possibly used unsafely; consider using mkstemp()

Would you mind using mkstemp() instead of tempnam()?

Gerald