Use AC_TRY_RUN instead of AC_TRY_LINK when checking for x86 PAUSE instruction support, due to http://bugs.opensolaris.org/bugdatabase/printableBug.do?bug_id=6478684 .

configure.in

@@ -2357,10 +2357,20 @@ fi
 
 #Check for x86 PAUSE instruction
 AC_MSG_CHECKING("for x86 PAUSE instruction")
-AC_TRY_COMPILE(
-[],
-[{__asm__ __volatile__ ("pause");}],
-x86_pause_exists=yes, x86_pause_exists=no)
+# We have to actually try running the test program, because of a bug
+# in Solaris on x86_64, where it wrongly reports that PAUSE is not
+# supported when trying to run an application.  See
+# http://bugs.opensolaris.org/bugdatabase/printableBug.do?bug_id=6478684
+AC_TRY_RUN([
+    int main() {
+      __asm__ __volatile__ ("pause");
+      return 0;
+    }
+  ],
+  [x86_pause_exists=yes],
+  [x86_pause_exists=no],
+  [x86_pause_exists=no]  # Cross-compile, assume no PAUSE instruction
+)
 if test "$x86_pause_exists" = "yes"
 then
   AC_DEFINE([HAVE_PAUSE_INSTRUCTION], [1], [Does x86 PAUSE instruction exist])