Produce the expected N/A error code in the OpenCL VLOOKUP implementation

Instead of a bare NaN.

Change-Id: I170c540478315eedd23f5851d54c30175d21ef96

sc/source/core/opencl/formulagroupcl.cxx

@@ -40,6 +40,7 @@ static const char* publicFunc =
  "#define errIllegalFPOperation 503 // #NUM!\n"
  "#define errNoValue 519 // #VALUE!\n"
  "#define errDivisionByZero 532 // #DIV/0!\n"
+ "#define NOTAVAILABLE 0x7fff // #N/A\n"
  "\n"
  "double CreateDoubleError(ulong nErr)\n"
  "{\n"

sc/source/core/opencl/op_spreadsheet.cxx

@@ -35,7 +35,7 @@ void OpVLookup::GenSlidingWindowFunction(std::stringstream &ss,
     }
     ss << ")\n    {\n";
     ss << "    int gid0=get_global_id(0);\n";
-    ss << "    double tmp = NAN;\n";
+    ss << "    double tmp = CreateDoubleError(NOTAVAILABLE);\n";
     ss << "    double intermediate = DBL_MAX;\n";
     ss << "    int singleIndex = gid0;\n";
     ss << "    int rowNum = -1;\n";