custom-build: corrected syntax to dereference HAVE_UNWIND_H properly

third_party/CMakeLists.txt

@@ -26,9 +26,9 @@ macro (luajit_build)
         set (luajit_copt ${luajit_copt} -O1)
         set (luajit_buildoptions ${luajit_buildoptions} XCFLAGS='-DLUA_USE_APICHECK -DLUA_USE_ASSERT')
     else ()
-    set (luajit_copt ${luajit_copt} -O2)
+	set (luajit_copt ${luajit_copt} -O2)
     endif()
-    if (NOT ${HAVE_UNWIND_H})
+    if (NOT HAVE_UNWIND_H)
         set (luajit_copt ${luajit_copt} -I${PROJECT_SOURCE_DIR}/third_party/compat)
     endif()
     set (luajit_buildoptions ${luajit_buildoptions} CCOPT="${luajit_copt}")