Fail gracefully if unable to open the opencl files.
diff --git a/ocl.c b/ocl.c
index cb95994..9c86161 100644
--- a/ocl.c
+++ b/ocl.c
@@ -367,6 +367,9 @@ _clState *initCl(unsigned int gpu, char *name, size_t nameSize)
char *source, *rawsource = file_contents(filename, &pl);
size_t sourceSize[] = {(size_t)pl};
+ if (!rawsource)
+ return NULL;
+
source = malloc(pl);
if (!source) {
applog(LOG_ERR, "Unable to malloc source");