Revert "Revert "Cleanup transitive includes in the legacy inlines.""

This reverts commit 9cb8639b18bc90dab461b4709607083301c9f6fc.

Fixed all the broken builds that were reported to me before this was
reverted.

Test: make checkbuild  # kikey960, marlin, aosp_arm64; master and aosp
diff --git a/libc/include/android/legacy_errno_inlines.h b/libc/include/android/legacy_errno_inlines.h
index 8f08074..9f116fa 100644
--- a/libc/include/android/legacy_errno_inlines.h
+++ b/libc/include/android/legacy_errno_inlines.h
@@ -29,11 +29,12 @@
 #ifndef _ANDROID_LEGACY_ERRNO_INLINES_H
 #define _ANDROID_LEGACY_ERRNO_INLINES_H
 
-#include <errno.h>
 #include <sys/cdefs.h>
 
 #if __ANDROID_API__ < __ANDROID_API_L__
 
+#include <errno.h>
+
 __BEGIN_DECLS
 
 static __inline int __attribute__((deprecated)) __set_errno(int n) {