diff --git a/configure.ac b/configure.ac
index 63a012b35df..febb352cdbe 100644
--- a/configure.ac
+++ b/configure.ac
@@ -968,22 +968,6 @@ AC_CHECK_DECLS([setsid])
 
 AC_CHECK_DECLS([pipe2])
 
-AC_MSG_CHECKING([for __builtin_clzl])
-AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[ ]], [[
- (void) __builtin_clzl(0);
-  ]])],
- [ AC_MSG_RESULT([yes]); have_clzl=yes; AC_DEFINE([HAVE_BUILTIN_CLZL], [1], [Define this symbol if you have __builtin_clzl])],
- [ AC_MSG_RESULT([no]); have_clzl=no;]
-)
-
-AC_MSG_CHECKING([for __builtin_clzll])
-AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[ ]], [[
-  (void) __builtin_clzll(0);
-  ]])],
- [ AC_MSG_RESULT([yes]); have_clzll=yes; AC_DEFINE([HAVE_BUILTIN_CLZLL], [1], [Define this symbol if you have __builtin_clzll])],
- [ AC_MSG_RESULT([no]); have_clzll=no;]
-)
-
 dnl Check for malloc_info (for memory statistics information in getmemoryinfo)
 AC_MSG_CHECKING([for getmemoryinfo])
 AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <malloc.h>]],
@@ -1736,7 +1720,6 @@ AM_CONDITIONAL([USE_UPNP], [test "$use_upnp" = "yes"])
 
 dnl for minisketch
 AM_CONDITIONAL([ENABLE_CLMUL], [test "$enable_clmul" = "yes"])
-AM_CONDITIONAL([HAVE_CLZ], [test "$have_clzl$have_clzll" = "yesyes"])
 
 AC_DEFINE([CLIENT_VERSION_MAJOR], [_CLIENT_VERSION_MAJOR], [Major version])
 AC_DEFINE([CLIENT_VERSION_MINOR], [_CLIENT_VERSION_MINOR], [Minor version])
diff --git a/src/Makefile.minisketch.include b/src/Makefile.minisketch.include
index 1363bec34ea..c6f894f0ca0 100644
--- a/src/Makefile.minisketch.include
+++ b/src/Makefile.minisketch.include
@@ -12,10 +12,6 @@ LIBMINISKETCH_CPPFLAGS += -DHAVE_CLMUL
 MINISKETCH_LIBS += $(LIBMINISKETCH_CLMUL)
 endif
 
-if HAVE_CLZ
-LIBMINISKETCH_CPPFLAGS += -DHAVE_CLZ
-endif
-
 EXTRA_LIBRARIES += $(MINISKETCH_LIBS)
 
 minisketch_libminisketch_clmul_a_SOURCES = $(MINISKETCH_FIELD_CLMUL_SOURCES_INT) $(MINISKETCH_FIELD_CLMUL_HEADERS_INT)