Get rid of configure check for __builtin_prefetch. All supported gcc-like compilers have it now.

Author: insertinterestingnamehere

config/qthread_check_attributes.m4

@@ -77,21 +77,6 @@ __attribute__((noinline)) void * f(int i)
  AS_IF([test "x$qt_cv_noinline_attr" = xyes], [$1], [$2])
 ])
 
-AC_DEFUN([QTHREAD_BUILTIN_PREFETCH],[dnl
-AC_CACHE_CHECK(
- [support for __builtin_prefetch],
- [qt_cv_builtin_prefetch],
- [AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <stdlib.h>
-int x;]],[[
-__builtin_prefetch(&x, 0, 0);
-return malloc(x)?1:0;]])],
- [qt_cv_builtin_prefetch=yes],
- [qt_cv_builtin_prefetch=no])])
- AS_IF([test "x$qt_cv_builtin_prefetch" = xyes],
- 	   [AC_DEFINE([HAS_BUILTIN_PREFETCH], [1], [define if compiler supports __builtin_prefetch])
-	   $1], [$2])
-])
-
 AC_DEFUN([QTHREAD_BUILTIN_SYNCHRONIZE],[dnl
 AC_REQUIRE([QTHREAD_CHECK_ASSEMBLY])
 AC_CACHE_CHECK([support for __sync_synchronize],

configure.ac

@@ -621,7 +621,6 @@ QTHREAD_UNUSED_ATTRIBUTE
 QTHREAD_ALIGNED_ATTRIBUTE
 QTHREAD_NOINLINE_ATTRIBUTE
 QTHREAD_DEPRECATED_ATTRIBUTE
-QTHREAD_BUILTIN_PREFETCH
 QTHREAD_BUILTIN_SYNCHRONIZE
 
 AS_IF([test "x$have_assembly" = "x0" -a "x$qthread_cv_atomic_CAS32" = "xno" -a "x$qthread_cv_atomic_CAS64" = "xno" -a "x$qthread_cv_atomic_incr" = "xno"],

include/qt_prefetch.h

@@ -1,7 +1,7 @@
 #ifndef QTHREAD_PREFETCH_H
 #define QTHREAD_PREFETCH_H
 
-#ifdef HAS_BUILTIN_PREFETCH
+#ifdef __GNUC__
 #define Q_PREFETCH(x, ...) __builtin_prefetch((x), ##__VA_ARGS__)
 #else
 #define Q_PREFETCH(x, ...)