Mesa (master): Make configure work with clang

[Eric Anholt]

Module: Mesa
Branch: master
Commit: 2a50187a923eb8950bc8b63f50eaea4704d6dc36
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=2a50187a923eb8950bc8b63f50eaea4704d6dc36

Author: nobled <nobled at dreamwidth.org>
Date:   Sun Aug 29 20:03:37 2010 -0400

Make configure work with clang

It was mistaking clang for gcc and deciding its version
was too low.

---

 configure.ac |   16 +++++++++++++++-
 1 files changed, 15 insertions(+), 1 deletions(-)

diff --git a/configure.ac b/configure.ac
index 4518854..cf2e200 100644
--- a/configure.ac
+++ b/configure.ac
@@ -48,9 +48,23 @@ solaris*)
     ;;
 esac
 
+dnl clang is mostly GCC-compatible, but its version is much lower,
+dnl so we have to check for it.
+AC_MSG_CHECKING([if compiling with clang])
+
+AC_COMPILE_IFELSE(
+[AC_LANG_PROGRAM([], [[
+#ifndef __clang__
+       not clang
+#endif
+]])],
+[CLANG=yes], [CLANG=no])
+
+AC_MSG_RESULT([$CLANG])
+
 dnl If we're using GCC, make sure that it is at least version 3.3.0.  Older
 dnl versions are explictly not supported.
-if test "x$GCC" = xyes; then
+if test "x$GCC" = xyes -a "x$CLANG" = xno; then
     AC_MSG_CHECKING([whether gcc version is sufficient])
     major=0
     minor=0