Fix CMake syntax to enable memory analyzer tests

"option" requires the help text as second, not as third argument. This
resulted in memory analyzer tests being disabled no matter what the OS
being built on.

Author: tautschnig

CMakeLists.txt

@@ -182,17 +182,14 @@ function(cprover_default_properties)
      XCODE_ATTRIBUTE_CODE_SIGN_IDENTITY ${CBMC_XCODE_ATTRIBUTE_CODE_SIGN_IDENTITY})
 endfunction()
 
-option(WITH_MEMORY_ANALYZER OFF
-  "build the memory analyzer")
-
 if(CMAKE_SYSTEM_NAME STREQUAL Linux)
 set(WITH_MEMORY_ANALYZER_DEFAULT ON)
 else()
 set(WITH_MEMORY_ANALYZER_DEFAULT OFF)
 endif()
 
-option(WITH_MEMORY_ANALYZER ${WITH_MEMORY_ANALYZER_DEFAULT}
-  "build the memory analyzer")
+option(WITH_MEMORY_ANALYZER
+  "build the memory analyzer" ${WITH_MEMORY_ANALYZER_DEFAULT})
 
 add_subdirectory(src)
 add_subdirectory(regression)