diff --git a/libc/include/stdatomic.h b/libc/include/stdatomic.h
index 013407e..3c61334 100644
--- a/libc/include/stdatomic.h
+++ b/libc/include/stdatomic.h
@@ -33,11 +33,7 @@
 #include <sys/cdefs.h>
 
 #if defined(__cplusplus) && __cplusplus >= 201103L && defined(_USING_LIBCXX)
-# ifdef __clang__
-#  if __has_feature(cxx_atomic)
-#   define _STDATOMIC_HAVE_ATOMIC
-#  endif
-# else /* gcc */
+# if __has_feature(cxx_atomic)
 #  define _STDATOMIC_HAVE_ATOMIC
 # endif
 #endif
@@ -150,20 +146,6 @@
 # include <uchar.h>  /* For char16_t and char32_t.              */
 #endif
 
-
-#ifdef __clang__
-# if __has_extension(c_atomic) || __has_extension(cxx_atomic)
-#  define       __CLANG_ATOMICS
-# else
-#  error "stdatomic.h does not support your compiler"
-# endif
-# if __has_builtin(__sync_swap)
-#  define __HAS_BUILTIN_SYNC_SWAP
-# endif
-#else
-# define __GNUC_ATOMICS
-#endif
-
 /*
  * 7.17.1 Atomic lock-free macros.
  */
@@ -203,13 +185,8 @@
  * 7.17.2 Initialization.
  */
 
-#if defined(__CLANG_ATOMICS)
 #define	ATOMIC_VAR_INIT(value)		(value)
 #define	atomic_init(obj, value)		__c11_atomic_init(obj, value)
-#else
-#define	ATOMIC_VAR_INIT(value)		{ .__val = (value) }
-#define	atomic_init(obj, value)		((void)((obj)->__val = (value)))
-#endif
 
 /*
  * Clang and recent GCC both provide predefined macros for the memory
@@ -258,63 +235,24 @@
  * 7.17.4 Fences.
  */
 
-static __inline void
-atomic_thread_fence(memory_order __order __attribute__((unused)))
-{
-
-#ifdef __CLANG_ATOMICS
+static __inline void atomic_thread_fence(memory_order __order __attribute__((unused))) {
 	__c11_atomic_thread_fence(__order);
-#elif defined(__GNUC_ATOMICS)
-	__atomic_thread_fence(__order);
-#else
-	__sync_synchronize();
-#endif
 }
 
-static __inline void
-atomic_signal_fence(memory_order __order __attribute__((unused)))
-{
-
-#ifdef __CLANG_ATOMICS
+static __inline void atomic_signal_fence(memory_order __order __attribute__((unused))) {
 	__c11_atomic_signal_fence(__order);
-#elif defined(__GNUC_ATOMICS)
-	__atomic_signal_fence(__order);
-#else
-	__asm volatile ("" ::: "memory");
-#endif
 }
 
 /*
  * 7.17.5 Lock-free property.
  */
 
-#if defined(_KERNEL)
-/* Atomics in kernelspace are always lock-free. */
-#define	atomic_is_lock_free(obj) \
-	((void)(obj), (_Bool)1)
-#elif defined(__CLANG_ATOMICS)
-#define	atomic_is_lock_free(obj) \
-	__c11_atomic_is_lock_free(sizeof(*(obj)))
-#elif defined(__GNUC_ATOMICS)
-#define	atomic_is_lock_free(obj) \
-	__atomic_is_lock_free(sizeof((obj)->__val), &(obj)->__val)
-#else
-#define	atomic_is_lock_free(obj) \
-	((void)(obj), sizeof((obj)->__val) <= sizeof(void *))
-#endif
+#define	atomic_is_lock_free(obj) __c11_atomic_is_lock_free(sizeof(*(obj)))
 
 /*
  * 7.17.6 Atomic integer types.
  */
 
-#ifndef __CLANG_ATOMICS
-/*
- * No native support for _Atomic(). Place object in structure to prevent
- * most forms of direct non-atomic access.
- */
-#define _Atomic(T)              struct { T volatile __val; }
-#endif
-
 typedef _Atomic(bool)			atomic_bool;
 typedef _Atomic(char)			atomic_char;
 typedef _Atomic(signed char)		atomic_schar;
@@ -363,7 +301,6 @@
  * Compiler-specific operations.
  */
 
-#if defined(__CLANG_ATOMICS)
 #define	atomic_compare_exchange_strong_explicit(object, expected,	\
     desired, success, failure)						\
 	__c11_atomic_compare_exchange_strong(object, expected, desired,	\
@@ -388,91 +325,11 @@
 	__c11_atomic_load(object, order)
 #define	atomic_store_explicit(object, desired, order)			\
 	__c11_atomic_store(object, desired, order)
-#elif defined(__GNUC_ATOMICS)
-#define	atomic_compare_exchange_strong_explicit(object, expected,	\
-    desired, success, failure)						\
-	__atomic_compare_exchange_n(&(object)->__val, expected,		\
-	    desired, 0, success, failure)
-#define	atomic_compare_exchange_weak_explicit(object, expected,		\
-    desired, success, failure)						\
-	__atomic_compare_exchange_n(&(object)->__val, expected,		\
-	    desired, 1, success, failure)
-#define	atomic_exchange_explicit(object, desired, order)		\
-	__atomic_exchange_n(&(object)->__val, desired, order)
-#define	atomic_fetch_add_explicit(object, operand, order)		\
-	__atomic_fetch_add(&(object)->__val, operand, order)
-#define	atomic_fetch_and_explicit(object, operand, order)		\
-	__atomic_fetch_and(&(object)->__val, operand, order)
-#define	atomic_fetch_or_explicit(object, operand, order)		\
-	__atomic_fetch_or(&(object)->__val, operand, order)
-#define	atomic_fetch_sub_explicit(object, operand, order)		\
-	__atomic_fetch_sub(&(object)->__val, operand, order)
-#define	atomic_fetch_xor_explicit(object, operand, order)		\
-	__atomic_fetch_xor(&(object)->__val, operand, order)
-#define	atomic_load_explicit(object, order)				\
-	__atomic_load_n(&(object)->__val, order)
-#define	atomic_store_explicit(object, desired, order)			\
-	__atomic_store_n(&(object)->__val, desired, order)
-#else
-#define	__atomic_apply_stride(object, operand) \
-	(((__typeof__((object)->__val))0) + (operand))
-#define	atomic_compare_exchange_strong_explicit(object, expected,	\
-    desired, success, failure)	__extension__ ({			\
-	__typeof__(expected) __ep = (expected);				\
-	__typeof__(*__ep) __e = *__ep;					\
-	(void)(success); (void)(failure);				\
-	(bool)((*__ep = __sync_val_compare_and_swap(&(object)->__val,	\
-	    __e, desired)) == __e);					\
-})
-#define	atomic_compare_exchange_weak_explicit(object, expected,		\
-    desired, success, failure)						\
-	atomic_compare_exchange_strong_explicit(object, expected,	\
-		desired, success, failure)
-#ifdef __HAS_BUILTIN_SYNC_SWAP
-/* Clang provides a full-barrier atomic exchange - use it if available. */
-#define	atomic_exchange_explicit(object, desired, order)		\
-	((void)(order), __sync_swap(&(object)->__val, desired))
-#else
-/*
- * __sync_lock_test_and_set() is only an acquire barrier in theory (although in
- * practice it is usually a full barrier) so we need an explicit barrier before
- * it.
- */
-#define	atomic_exchange_explicit(object, desired, order)		\
-__extension__ ({							\
-	__typeof__(object) __o = (object);				\
-	__typeof__(desired) __d = (desired);				\
-	(void)(order);							\
-	__sync_synchronize();						\
-	__sync_lock_test_and_set(&(__o)->__val, __d);			\
-})
-#endif
-#define	atomic_fetch_add_explicit(object, operand, order)		\
-	((void)(order), __sync_fetch_and_add(&(object)->__val,		\
-	    __atomic_apply_stride(object, operand)))
-#define	atomic_fetch_and_explicit(object, operand, order)		\
-	((void)(order), __sync_fetch_and_and(&(object)->__val, operand))
-#define	atomic_fetch_or_explicit(object, operand, order)		\
-	((void)(order), __sync_fetch_and_or(&(object)->__val, operand))
-#define	atomic_fetch_sub_explicit(object, operand, order)		\
-	((void)(order), __sync_fetch_and_sub(&(object)->__val,		\
-	    __atomic_apply_stride(object, operand)))
-#define	atomic_fetch_xor_explicit(object, operand, order)		\
-	((void)(order), __sync_fetch_and_xor(&(object)->__val, operand))
-#define	atomic_load_explicit(object, order)				\
-	((void)(order), __sync_fetch_and_add(&(object)->__val, 0))
-#define	atomic_store_explicit(object, desired, order)			\
-	((void)atomic_exchange_explicit(object, desired, order))
-#endif
 
 /*
  * Convenience functions.
- *
- * Don't provide these in kernel space. In kernel space, we should be
- * disciplined enough to always provide explicit barriers.
  */
 
-#ifndef _KERNEL
 #define	atomic_compare_exchange_strong(object, expected, desired)	\
 	atomic_compare_exchange_strong_explicit(object, expected,	\
 	    desired, memory_order_seq_cst, memory_order_seq_cst)
@@ -495,7 +352,6 @@
 	atomic_load_explicit(object, memory_order_seq_cst)
 #define	atomic_store(object, desired)					\
 	atomic_store_explicit(object, desired, memory_order_seq_cst)
-#endif /* !_KERNEL */
 
 /*
  * 7.17.8 Atomic flag type and operations.
@@ -510,36 +366,21 @@
 
 #define	ATOMIC_FLAG_INIT		{ ATOMIC_VAR_INIT(false) }
 
-static __inline bool
-atomic_flag_test_and_set_explicit(volatile atomic_flag *__object,
-    memory_order __order)
-{
+static __inline bool atomic_flag_test_and_set_explicit(volatile atomic_flag *__object, memory_order __order) {
 	return (atomic_exchange_explicit(&__object->__flag, 1, __order));
 }
 
-static __inline void
-atomic_flag_clear_explicit(volatile atomic_flag *__object, memory_order __order)
-{
-
+static __inline void atomic_flag_clear_explicit(volatile atomic_flag *__object, memory_order __order) {
 	atomic_store_explicit(&__object->__flag, 0, __order);
 }
 
-#ifndef _KERNEL
-static __inline bool
-atomic_flag_test_and_set(volatile atomic_flag *__object)
-{
-
-	return (atomic_flag_test_and_set_explicit(__object,
-	    memory_order_seq_cst));
+static __inline bool atomic_flag_test_and_set(volatile atomic_flag *__object) {
+	return (atomic_flag_test_and_set_explicit(__object, memory_order_seq_cst));
 }
 
-static __inline void
-atomic_flag_clear(volatile atomic_flag *__object)
-{
-
+static __inline void atomic_flag_clear(volatile atomic_flag *__object) {
 	atomic_flag_clear_explicit(__object, memory_order_seq_cst);
 }
-#endif /* !_KERNEL */
 
 #endif /* <atomic> unavailable */