ENH: add INFINITY to CUDA kernel preamble

Author: Holger Kohr

src/gpuarray_buffer_cuda.c

@@ -318,6 +318,10 @@ static const char CUDA_PREAMBLE[] =
     "#undef NAN\n"
     "#endif\n"
     "#define NAN __int_as_float(0x7fffffff)\n"
+    "#ifdef INFINITY\n"
+    "#undef INFINITY\n"
+    "#endif\n"
+    "#define INFINITY __int_as_float(0x7f800000)\n"
     "#define LID_0 threadIdx.x\n"
     "#define LID_1 threadIdx.y\n"
     "#define LID_2 threadIdx.z\n"