Pointer Casting KSU Compile Error Samsung 4.9

[addas]

I am getting this error, I tried Google searching but nothing found

I am somehow confident I did almost everything correct using manually KSU implementation

CC drivers/kernelsu/apk_sign.o
drivers/kernelsu/apk_sign.c: In function 'check_block':
drivers/kernelsu/apk_sign.c:101:14: error: passing argument 1 of 'IS_ERR' makes pointer from integer without a cast [-Werror]
if (IS_ERR(ksu_sha256(cert, *size4, digest))) {
^
In file included from drivers/kernelsu/apk_sign.c:1:0:
./include/linux/err.h:33:33: note: expected 'const void *' but argument is of type 'int'
static inline bool __must_check IS_ERR(__force const void *ptr)
^
drivers/kernelsu/apk_sign.c: At top level:
cc1: error: unrecognized command line option "-Wno-gcc-compat" [-Werror]
cc1: error: unrecognized command line option "-Wno-int-conversion" [-Werror]
cc1: all warnings being treated as errors
make[2]: *** [scripts/Makefile.build:334: drivers/kernelsu/apk_sign.o] Error 1
make[1]: *** [scripts/Makefile.build:648: drivers/kernelsu] Error 2
make: *** [Makefile:1121: drivers] Error 2
make: *** Waiting for unfinished jobs...