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/android/legacy_unistd_inlines.h b/libc/include/android/legacy_unistd_inlines.h
index ac9f3b3..4a5206b 100644
--- a/libc/include/android/legacy_unistd_inlines.h
+++ b/libc/include/android/legacy_unistd_inlines.h
@@ -32,7 +32,7 @@
 
 #if __ANDROID_API__ < 28
 
-#define __BIONIC_SWAB_INLINE static inline
+#define __BIONIC_SWAB_INLINE static __inline
 #include <bits/swab.h>
 
 #endif