Fix the PAUSE instruction handling in InnoDB

Previously HAVE_IB_PAUSE_INSTRUCTION was never defined and thus InnoDB
never used the PAUSE instruction on non-windows even if it was available.
Probably the check was never migrated from autotools'
storage/innobase/plug.in to storage/innobase/CMakeLists.txt.

Since the check for PAUSE is done at top-level configure.cmake we can
use the result from there (HAVE_PAUSE_INSTRUCTION) instead of rolling
InnoDB's own HAVE_IB_PAUSE_INSTRUCTION (the check is identical anyway).

storage/innobase/CMakeLists.txt

@@ -189,7 +189,7 @@ IF(SIZEOF_PTHREAD_T)
 ENDIF()
 
 IF(MSVC)
-  ADD_DEFINITIONS(-DHAVE_WINDOWS_ATOMICS -DHAVE_IB_PAUSE_INSTRUCTION)
+  ADD_DEFINITIONS(-DHAVE_WINDOWS_ATOMICS)
 ENDIF()
 
 

storage/innobase/include/ut0ut.h

@@ -55,24 +55,22 @@ Created 1/20/1994 Heikki Tuuri
 typedef time_t	ib_time_t;
 
 #ifndef UNIV_HOTBACKUP
-#if defined(HAVE_IB_PAUSE_INSTRUCTION)
-#  ifdef WIN32
-     /* In the Win32 API, the x86 PAUSE instruction is executed by calling
-     the YieldProcessor macro defined in WinNT.h. It is a CPU architecture-
-     independent way by using YieldProcessor.*/
-#    define UT_RELAX_CPU() YieldProcessor()
-#  else
-     /* According to the gcc info page, asm volatile means that the
-     instruction has important side-effects and must not be removed.
-     Also asm volatile may trigger a memory barrier (spilling all registers
-     to memory). */
-#    define UT_RELAX_CPU() __asm__ __volatile__ ("pause")
-#  endif
+#if defined(HAVE_PAUSE_INSTRUCTION)
+   /* According to the gcc info page, asm volatile means that the
+   instruction has important side-effects and must not be removed.
+   Also asm volatile may trigger a memory barrier (spilling all registers
+   to memory). */
+#  define UT_RELAX_CPU() __asm__ __volatile__ ("pause")
 #elif defined(HAVE_ATOMIC_BUILTINS)
 #  define UT_RELAX_CPU() do { \
      volatile lint	volatile_var; \
      os_compare_and_swap_lint(&volatile_var, 0, 1); \
    } while (0)
+#elif defined(HAVE_WINDOWS_ATOMICS)
+   /* In the Win32 API, the x86 PAUSE instruction is executed by calling
+   the YieldProcessor macro defined in WinNT.h. It is a CPU architecture-
+   independent way by using YieldProcessor. */
+#  define UT_RELAX_CPU() YieldProcessor()
 #else
 #  define UT_RELAX_CPU() ((void)0) /* avoid warning for an empty statement */
 #endif