Use inline keyword without underscores consistently

s/__inline__/inline
s/__inline/inline

Change-Id: I5d8d930a7a41d678a0795e7a608dacbb9eb8cb37
diff --git a/libc/include/bits/threads_inlines.h b/libc/include/bits/threads_inlines.h
index 5878e0a..074e1ca 100644
--- a/libc/include/bits/threads_inlines.h
+++ b/libc/include/bits/threads_inlines.h
@@ -38,7 +38,7 @@
 
 __BEGIN_DECLS
 
-static __inline int __bionic_thrd_error(int __pthread_code) {
+static inline int __bionic_thrd_error(int __pthread_code) {
   switch (__pthread_code) {
     case 0: return 0;
     case ENOMEM: return thrd_nomem;