Revert "Use inline keyword without underscores consistently"

This reverts commit 58f06e11122723d68c5cb393aeb4ed1c7a2e7bfe.

Bare `inline` is not ANSI C compatible, and NDK users may be using
that.

Test: treehugger
Change-Id: I82c5424522142001cd59da63ef3fd440014451ad
diff --git a/libc/include/bits/stdatomic.h b/libc/include/bits/stdatomic.h
index 8df86e2..c74eafd 100644
--- a/libc/include/bits/stdatomic.h
+++ b/libc/include/bits/stdatomic.h
@@ -138,11 +138,11 @@
  * 7.17.4 Fences.
  */
 
-static inline void atomic_thread_fence(memory_order __order __attribute__((__unused__))) {
+static __inline void atomic_thread_fence(memory_order __order __attribute__((__unused__))) {
 	__c11_atomic_thread_fence(__order);
 }
 
-static inline void atomic_signal_fence(memory_order __order __attribute__((__unused__))) {
+static __inline void atomic_signal_fence(memory_order __order __attribute__((__unused__))) {
 	__c11_atomic_signal_fence(__order);
 }
 
@@ -269,18 +269,18 @@
 
 #define	ATOMIC_FLAG_INIT		{ ATOMIC_VAR_INIT(false) }
 
-static inline bool atomic_flag_test_and_set_explicit(volatile atomic_flag * _Nonnull __object, memory_order __order) {
+static __inline bool atomic_flag_test_and_set_explicit(volatile atomic_flag * _Nonnull __object, memory_order __order) {
 	return (atomic_exchange_explicit(&__object->__flag, 1, __order));
 }
 
-static inline void atomic_flag_clear_explicit(volatile atomic_flag * _Nonnull __object, memory_order __order) {
+static __inline void atomic_flag_clear_explicit(volatile atomic_flag * _Nonnull __object, memory_order __order) {
 	atomic_store_explicit(&__object->__flag, 0, __order);
 }
 
-static inline bool atomic_flag_test_and_set(volatile atomic_flag * _Nonnull __object) {
+static __inline bool atomic_flag_test_and_set(volatile atomic_flag * _Nonnull __object) {
 	return (atomic_flag_test_and_set_explicit(__object, memory_order_seq_cst));
 }
 
-static inline void atomic_flag_clear(volatile atomic_flag * _Nonnull __object) {
+static __inline void atomic_flag_clear(volatile atomic_flag * _Nonnull __object) {
 	atomic_flag_clear_explicit(__object, memory_order_seq_cst);
 }