OSX: get cache line size

cmake/cpu_info.cmake

@@ -15,15 +15,29 @@
 
 # Symbols with information about the CPU.
 
-FIND_PROGRAM(GETCONF getconf)
-MARK_AS_ADVANCED(GETCONF)
+IF(CMAKE_SYSTEM_NAME MATCHES "Darwin")
+  FIND_PROGRAM(SYSCTL sysctl)
+  MARK_AS_ADVANCED(SYSCTL)
 
-IF(GETCONF)
-  EXECUTE_PROCESS(
-    COMMAND ${GETCONF} LEVEL1_DCACHE_LINESIZE
-    OUTPUT_VARIABLE CPU_LEVEL1_DCACHE_LINESIZE
-    )
+  IF(SYSCTL)
+    EXECUTE_PROCESS(
+      COMMAND ${SYSCTL} -n hw.cachelinesize
+      OUTPUT_VARIABLE CPU_LEVEL1_DCACHE_LINESIZE
+      )
+  ENDIF()
+
+ELSE()
+  FIND_PROGRAM(GETCONF getconf)
+  MARK_AS_ADVANCED(GETCONF)
+
+  IF(GETCONF)
+    EXECUTE_PROCESS(
+      COMMAND ${GETCONF} LEVEL1_DCACHE_LINESIZE
+      OUTPUT_VARIABLE CPU_LEVEL1_DCACHE_LINESIZE
+      )
+  ENDIF()
 ENDIF()
+
 IF(CPU_LEVEL1_DCACHE_LINESIZE AND CPU_LEVEL1_DCACHE_LINESIZE GREATER 0)
 ELSE()
   SET(CPU_LEVEL1_DCACHE_LINESIZE 64)