Configure: fixed clang detection on MINIX. As per POSIX, basic regular expressions have no alternations, and the interpretation of the "\|" construct is undefined. At least on MINIX and Solaris grep interprets "\|" as literal "|", and not as an alternation as GNU grep does. Removed such constructs introduced in f1daa0356a1d. This fixes clang detection on MINIX.

--- a/auto/cc/clang
+++ b/auto/cc/clang
@@ -5,7 +5,7 @@
 # clang
 
 
-NGX_CLANG_VER=`$CC -v 2>&1 | grep '\(clang\|LLVM\) version' 2>&1 \
+NGX_CLANG_VER=`$CC -v 2>&1 | grep 'version' 2>&1 \
                            | sed -e 's/^.* version \(.*\)/\1/'`
 
 echo " + clang version: $NGX_CLANG_VER"