Bug#539912: gcc-4.3: POSIX requires that option -D have a lower precedence than -U

[Vincent Lefevre <vincent@vinc17.org>]

Package: gcc-4.3
Version: 4.3.3-15
Severity: normal

Note: this is a bug concerning the c99 utility, but since c99 uses
gcc, I report the bug against gcc. Also note that both gcc-4.4 and
gcc-snapshot have the same problem. I've also reported the bug on
GCC's bugzilla: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40960

In http://www.opengroup.org/onlinepubs/9699919799/utilities/c99.html
POSIX specifies:

  -D  name[=value]
    Define name as if by a C-language #define directive. If no = value
    is given, a value of 1 shall be used. The -D option has lower
    precedence than the -U option. That is, if name is used in both a
    -U and a -D option, name shall be undefined regardless of the
    order of the options.

However, gcc doesn't take the precedence rule into account:

$ cat tst.c
int main(void)
{
#ifdef FOO
  return 1;
#else
  return 0;
#endif
}
$ c99 tst.c -UFOO -DFOO=1
$ ./a.out
zsh: exit 1     ./a.out

whereas FOO should be undefined and the return value should be 0, not 1.

-- System Information:
Debian Release: squeeze/sid
  APT prefers unstable
  APT policy: (500, 'unstable'), (500, 'stable')
Architecture: amd64 (x86_64)

Kernel: Linux 2.6.30-1-amd64 (SMP w/2 CPU cores)
Locale: LANG=POSIX, LC_CTYPE=en_US.ISO8859-1 (charmap=ISO-8859-1)
Shell: /bin/sh linked to /bin/dash

Versions of packages gcc-4.3 depends on:
ii  binutils              2.19.51.20090723-1 The GNU assembler, linker and bina
ii  cpp-4.3               4.3.3-15           The GNU C preprocessor
ii  gcc-4.3-base          4.3.3-15           The GNU Compiler Collection (base 
ii  libc6                 2.9-23             GNU C Library: Shared libraries
ii  libgcc1               1:4.4.1-1          GCC support library
ii  libgomp1              4.4.1-1            GCC OpenMP (GOMP) support library

Versions of packages gcc-4.3 recommends:
ii  libc6-dev                     2.9-23     GNU C Library: Development Librari

Versions of packages gcc-4.3 suggests:
ii  gcc-4.3-doc                  4.3.2.nf1-1 documentation for the GNU compiler
pn  gcc-4.3-locales              <none>      (no description available)
pn  gcc-4.3-multilib             <none>      (no description available)
pn  libgcc1-dbg                  <none>      (no description available)
pn  libgomp1-dbg                 <none>      (no description available)
pn  libmudflap0-4.3-dev          <none>      (no description available)
pn  libmudflap0-dbg              <none>      (no description available)

-- no debconf information