Can't compile project about resea

So I uncommented CFLAGS += -fstack-size-section and created a symlink sudo ln -s /usr/lib/llvm-9/bin/clang /usr/bin/clang and now make says

CC kernel/main.c
CC kernel/task.c
CC kernel/ipc.c
CC kernel/syscall.c
CC kernel/memory.c
CC kernel/printk.c
CC kernel/kdebug.c
CC kernel/arch/x64/task.c
CC kernel/arch/x64/vm.c
CC kernel/arch/x64/serial.c
CC servers/kvs/main.c
CC libs/std/init.c
CC libs/std/syscall.c
CC libs/std/printf.c
CC libs/std/malloc.c
CC libs/std/io.c
CC libs/std/lookup.c
CC libs/std/session.c
CC libs/std/async.c
CC libs/std/arch/x64/start.S
LD build/user/libs/std.o
CC libs/stubs/tcpip.c
LD build/user/libs/stubs.o
CC libs/common/string.c
CC libs/common/vprintf.c
CC libs/common/ubsan.c
CC libs/common/arch/x64/memcpy.S
LD build/user/kvs.debug.elf
SYMBOLS build/user/kvs.debug.elf
STRIP build/user/kvs.elf
CC servers/tcpip/main.c
CC servers/tcpip/arp.c
CC servers/tcpip/device.c
CC servers/tcpip/dhcp.c
CC servers/tcpip/ethernet.c
CC servers/tcpip/ipv4.c
CC servers/tcpip/mbuf.c
CC servers/tcpip/tcp.c
CC servers/tcpip/udp.c
CC servers/tcpip/stats.c
LD build/user/tcpip.debug.elf
SYMBOLS build/user/tcpip.debug.elf
STRIP build/user/tcpip.elf
CC servers/ps2kbd/main.c
LD build/user/ps2kbd.debug.elf
SYMBOLS build/user/ps2kbd.debug.elf
STRIP build/user/ps2kbd.elf
CC servers/display/main.c
LD build/user/display.debug.elf
SYMBOLS build/user/display.debug.elf
STRIP build/user/display.elf
CC servers/e1000/main.c
CC servers/e1000/e1000.c
CC servers/e1000/pci.c
LD build/user/e1000.debug.elf
SYMBOLS build/user/e1000.debug.elf
STRIP build/user/e1000.elf
CC servers/shell/main.c
LD build/user/shell.debug.elf
SYMBOLS build/user/shell.debug.elf
STRIP build/user/shell.elf
CC servers/webapi/main.c
LD build/user/webapi.debug.elf
SYMBOLS build/user/webapi.debug.elf
STRIP build/user/webapi.elf
CC servers/benchmark/main.c
LD build/user/benchmark.debug.elf
SYMBOLS build/user/benchmark.debug.elf
STRIP build/user/benchmark.elf
CC servers/hello/main.c
LD build/user/hello.debug.elf
SYMBOLS build/user/hello.debug.elf
STRIP build/user/hello.elf
CC servers/init/main.c
CC servers/init/pages.c
LD build/user/init.debug.elf
SYMBOLS build/user/init.debug.elf
STRIP build/user/init.elf
OBJCOPY build/init.bin
llvm-objcopy-6.0: 'build/user/init.elf': The file was not recognized as a valid object file
Makefile:107: recipe for target 'build/init.bin' failed
make: *** [build/init.bin] Error 1

[nuta]

LLVM/Clang 6.x is too old to build Resea. Could you try with version 8.x or higher?

Also, LLVM_SUFFIX option would be helpful:

$ make LLVM_SUFFIX=-8 run