Fix Wcast-qual warning. (#241)

* Fix Wcast-qual warning.

* Format

Author: haonanya1

loader/icd.c

@@ -326,11 +326,11 @@ void khrIcdLayerAdd(const char *libraryName)
 
     for (cl_uint i = 0; i < limit; i++) {
         ((void **)&(layer->dispatch))[i] =
-            ((void **)layerDispatch)[i] ?
-                ((void **)layerDispatch)[i] : ((void **)targetDispatch)[i];
+            ((void *const*)layerDispatch)[i] ?
+                ((void *const*)layerDispatch)[i] : ((void *const*)targetDispatch)[i];
     }
     for (cl_uint i = limit; i < loaderDispatchNumEntries; i++) {
-        ((void **)&(layer->dispatch))[i] = ((void **)targetDispatch)[i];
+        ((void **)&(layer->dispatch))[i] = ((void *const*)targetDispatch)[i];
     }
 
     KHR_ICD_TRACE("successfully added layer %s\n", libraryName);

loader/icd_dispatch.c

@@ -36,12 +36,12 @@ clGetICDLoaderInfoOCLICD(
     static const char cl_icdl_NAME[]        = OPENCL_ICD_LOADER_NAME_STRING;
     static const char cl_icdl_VENDOR[]      = OPENCL_ICD_LOADER_VENDOR_STRING;
     size_t            pvs;
-    void *            pv;
+    const void *      pv = NULL;
 
 #define KHR_ICD_CASE_STRING_PARAM_NAME(name)                                   \
     case CL_ICDL_ ## name:                                                     \
         pvs = strlen(cl_icdl_ ## name) + 1;                                    \
-        pv = (void *)cl_icdl_ ## name;                                         \
+        pv = (const void *)cl_icdl_ ## name;                                   \
         break
 
     switch (param_name) {

loader/linux/icd_linux.c

@@ -129,7 +129,7 @@ struct dirElem
 static int compareDirElem(const void *a, const void *b)
 {
     // sort files the same way libc alpahnumerically sorts directory entries.
-    return strcoll(((struct dirElem *)a)->d_name, ((struct dirElem *)b)->d_name);
+    return strcoll(((const struct dirElem *)a)->d_name, ((const struct dirElem *)b)->d_name);
 }
 
 static inline void khrIcdOsDirEnumerate(const char *path, const char *env,