diff --git a/CMakeLists.txt b/CMakeLists.txt
index a36eebf3c..ed24f79e2 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -717,13 +717,6 @@ if (HAIKU)
 	set(CMAKE_REQUIRED_LIBRARIES network)
 endif()
 
-CHECK_C_SOURCE_COMPILES(
-	"#include <strings.h>
-	#if __GNUC__
-	#pragma GCC diagnostic error \"-Wimplicit-function-declaration\"
-	#endif
-	int main(int argc, char **argv) { char buf[100]; bzero(buf, 100); return 0; }
-	" LWS_HAVE_BZERO)
 CHECK_C_SOURCE_COMPILES(
 	"#include <malloc.h>
 	int main(int argc, char **argv) { return malloc_trim(0); }
diff --git a/cmake/lws_config_private.h.in b/cmake/lws_config_private.h.in
index 10eea96e5..22afd64e0 100644
--- a/cmake/lws_config_private.h.in
+++ b/cmake/lws_config_private.h.in
@@ -10,9 +10,6 @@
  * LWS_OPENSSL_SUPPORT needs to be set also for this to work. */
 #cmakedefine USE_CYASSL
 
-/* Define to 1 if you have the `bzero' function. */
-#cmakedefine LWS_HAVE_BZERO
-
 /* Define to 1 if you have the <dlfcn.h> header file. */
 #cmakedefine LWS_HAVE_DLFCN_H