diff -Naur libilbc-3.0.4.old/rtc_base/system/arch.h libilbc-3.0.4/rtc_base/system/arch.h
--- libilbc-3.0.4.old/rtc_base/system/arch.h	2022-05-25 10:51:43.561630619 +0200
+++ libilbc-3.0.4/rtc_base/system/arch.h	2022-05-25 11:40:46.556337090 +0200
@@ -60,6 +60,8 @@
 #else
 #define WEBRTC_ARCH_BIG_ENDIAN
 #endif
+#elif defined(__s390__) || defined(__s390x__) || defined(__zarch__)
+#define WEBRTC_ARCH_BIG_ENDIAN
 #elif defined(__sparc) || defined(__sparc__)
 #if __SIZEOF_LONG__ == 8
 #define WEBRTC_ARCH_64_BITS