libspl: remove assembly atomics for i486 and amd64

These are only used by ztest and zdb, absolute speed isn't too big of a
concern

Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>

lib/libspl/Makefile.am

@@ -1,28 +1,15 @@
 include $(top_srcdir)/config/Rules.am
 
-if TARGET_CPU_I386
-TARGET_CPU_ATOMIC_SOURCE = asm-i386/atomic.S
-else
-if TARGET_CPU_X86_64
-TARGET_CPU_ATOMIC_SOURCE = asm-x86_64/atomic.S
-else
-TARGET_CPU_ATOMIC_SOURCE = asm-generic/atomic.c
-LIBATOMIC = $(LIBATOMIC_LIBS)
-endif
-endif
-
 SUBDIRS = include
 
-AM_CCASFLAGS = \
-	$(CFLAGS)
-
 noinst_LTLIBRARIES = libspl_assert.la libspl.la
 
 libspl_assert_la_SOURCES = \
 	assert.c
 
 USER_C = \
 	libspl_impl.h \
+	atomic.c \
 	getexecname.c \
 	list.c \
 	mkdirp.c \
@@ -50,20 +37,11 @@ USER_C += \
 	os/freebsd/zone.c
 endif
 
-libspl_la_SOURCES = \
-	$(USER_C) \
-	$(TARGET_CPU_ATOMIC_SOURCE)
+libspl_la_SOURCES = $(USER_C)
 
 libspl_la_LIBADD = \
 	libspl_assert.la
 
-libspl_la_LIBADD += $(LIBATOMIC) $(LIBCLOCK_GETTIME)
+libspl_la_LIBADD += $(LIBATOMIC_LIBS) $(LIBCLOCK_GETTIME)
 
 include $(top_srcdir)/config/CppCheck.am
-
-# Override the default SOURCES which includes TARGET_CPU_ATOMIC_SOURCE
-# in order to always evaluate the generic asm-generic/atomic.c source.
-CPPCHECKSRC = $(USER_C) asm-generic/atomic.c
-cppcheck:
-	$(CPPCHECK) -j$(CPU_COUNT) $(CPPCHECKFLAGS) --force \
-		$(DEFAULT_INCLUDES) $(CPPCHECKSRC)