Not all linux users will have libatomic installed.
When using clang as the system compiler with compiler-rt as the default
runtime library instead of libgcc, atomic builtins may be provided by compiler-rt.
This change allows such users to pass RTLIB=compiler-rt to make sure
the build doesn't error out on the missing (unnecessary) libatomic.
closes https://github.com/official-stockfish/Stockfish/pull/3597
No functional change
ifneq ($(KERNEL),Darwin)
ifneq ($(KERNEL),OpenBSD)
ifneq ($(KERNEL),FreeBSD)
+ ifneq ($(RTLIB),compiler-rt)
LDFLAGS += -latomic
endif
endif
endif
+ endif
ifeq ($(arch),$(filter $(arch),armv7 armv8))
ifeq ($(OS),Android)