diff --git a/mbedtls-sys/build/cmake.rs b/mbedtls-sys/build/cmake.rs
index f9254a31..07391e5a 100644
--- a/mbedtls-sys/build/cmake.rs
+++ b/mbedtls-sys/build/cmake.rs
@@ -17,6 +17,7 @@ impl super::BuildConfig {
         ))
         .define("ENABLE_PROGRAMS", "OFF")
         .define("ENABLE_TESTING", "OFF")
+        .define("MBEDTLS_FATAL_WARNINGS", "OFF")
         .build_target("lib");
         for cflag in &self.cflags {
             cmk.cflag(cflag);