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_fenv_inlines_arm.h b/libc/include/android/legacy_fenv_inlines_arm.h
index 58c49c2..f5b2828 100644
--- a/libc/include/android/legacy_fenv_inlines_arm.h
+++ b/libc/include/android/legacy_fenv_inlines_arm.h
@@ -29,10 +29,12 @@
 #ifndef ANDROID_LEGACY_FENV_INLINES_ARM_H
 #define ANDROID_LEGACY_FENV_INLINES_ARM_H
 
-#include <fenv.h>
+#include <sys/cdefs.h>
 
 #if __ANDROID_API__ < __ANDROID_API_L__ && defined(__arm__)
 
+#include <fenv.h>
+
 __BEGIN_DECLS
 
 #define FPSCR_ENABLE_SHIFT 8