diff --git a/zipl/boot/zlib/deflate.c b/zipl/boot/zlib/deflate.c
index 1b8b74b3..1dd502a0 100644
--- a/zipl/boot/zlib/deflate.c
+++ b/zipl/boot/zlib/deflate.c
@@ -115,7 +115,7 @@ typedef struct deflate_workspace {
 
 #ifdef CONFIG_ZLIB_DFLTCC
 /* dfltcc_state must be doubleword aligned for DFLTCC call */
-static_assert(offsetof(struct deflate_workspace, dfltcc_memory) % 8 == 0);
+STATIC_ASSERT(offsetof(struct deflate_workspace, dfltcc_memory) % 8 == 0);
 #endif
 
 /* Values for max_lazy_match, good_match and max_chain_length, depending on
diff --git a/zipl/boot/zlib/dfltcc.h b/zipl/boot/zlib/dfltcc.h
index 4256dfb3..f36e7899 100644
--- a/zipl/boot/zlib/dfltcc.h
+++ b/zipl/boot/zlib/dfltcc.h
@@ -2,9 +2,9 @@
 #ifndef DFLTCC_H
 #define DFLTCC_H
 
-#include "defutil.h"
 #include <stdint.h>
-#include <assert.h>
+#include "lib/zt_common.h"
+#include "defutil.h"
 
 /*
  * Tuning parameters.
@@ -28,7 +28,7 @@ struct dfltcc_qaf_param {
     char reserved2[6];
 };
 
-static_assert(sizeof(struct dfltcc_qaf_param) == 32);
+STATIC_ASSERT(sizeof(struct dfltcc_qaf_param) == 32);
 
 #define DFLTCC_FMT0 0
 
@@ -80,7 +80,7 @@ struct dfltcc_param_v0 {
     uint8_t csb[1152];
 };
 
-static_assert(sizeof(struct dfltcc_param_v0) == 1536);
+STATIC_ASSERT(sizeof(struct dfltcc_param_v0) == 1536);
 
 #define CVT_CRC32 0
 #define CVT_ADLER32 1