ffi: fix compilation errors #110

Job	Run time
android_ndk_lts (aarch64-linux-android)	58s
android_ndk_lts (armv7-linux-androideabi)	1m 2s
android_ndk_lts (x86_64-linux-android)	1m 3s
android_ndk_lts (i686-linux-android)	1m 3s
docker	3m 11s
http3_test	55s
nginx (1.16.1)	1m 11s
quiche	3m 23s
quiche_ios (x86_64-apple-ios)	1m 9s
quiche_macos (macos-13)	3m 30s
quiche (boringssl-boring-crate)	3m 15s
quiche_multiarch (aarch64-unknown-linux-gnu)	2m 45s
quiche_ios (aarch64-apple-ios)	1m 3s
quiche (openssl)	5m 59s
quiche_macos (macos-latest)	2m 1s
quiche_multiarch (armv7-unknown-linux-gnueabihf)	3m 0s
quiche_multiarch (i686-unknown-linux-gnu)	1m 37s
quiche_windows (x86_64-pc-windows-msvc)	3m 1s
quiche_windows (i686-pc-windows-msvc)	4m 21s
quiche_windows (x86_64-pc-windows-gnu)	5m 14s
quiche_windows (i686-pc-windows-gnu)	6m 12s
	55m 53s

Provide feedback