Re: AC_PROG_CC wrongly setting $GCC=yes while clang is used

[Paul Smith]

On Sun, 2014-09-07 at 22:52 +0200, Bastien Chevreux wrote:
> having used gcc for ages, I decided to try and play around with clang
> for one of my C/C++ projects. Unfortunately, it looks as if autoconf
> 2.69 gets things horribly wrong with clang.

In what way?  IIUC, configure has discovered that clang is close enough
to the GCC user interface that it can treat clang as GCC, for the
purposes of generating autoconf and automake scripts.

Is there actually any failure here?  Do the resulting Makefiles invoke
clang properly for compiling and linking?  Do they correctly handle
automatic dependencies?  If something fails or doesn't work right please
post those error messages, etc.

In particular, this:

  configure:3666: checking whether we are using the GNU C compiler
  configure:3685: clang -c -mmacosx-version-min=10.6    conftest.c >&5
  configure:3685: $? = 0
  configure:3694: result: yes

Appears to show that clang is defining the __GNUC__ built-in compiler
flag, presumably for compatibility with GCC source code.  So IF there's
any real problem here, which I'm not sure there is, the problem is in
clang claiming to be something it's not.