diff --git a/include/u-boot/zlib.h b/include/u-boot/zlib.h
index b611fe7c79..e23ceb50ca 100644
--- a/include/u-boot/zlib.h
+++ b/include/u-boot/zlib.h
@@ -505,7 +505,7 @@ typedef gz_header FAR *gz_headerp;
 #define Z_DEFLATED   8
 /* The deflate compression method (the only one supported in this version) */
 
-#define Z_NULL  0  /* for initializing zalloc, zfree, opaque */
+#define Z_NULL  (void *)0  /* for initializing zalloc, zfree, opaque */
 
                         /* basic functions */
 
diff --git a/lib/zlib/adler32.c b/lib/zlib/adler32.c
index dc9480d92f..b468441d73 100644
--- a/lib/zlib/adler32.c
+++ b/lib/zlib/adler32.c
@@ -54,10 +54,7 @@
 #endif
 
 /* ========================================================================= */
-uLong ZEXPORT adler32(adler, buf, len)
-    uLong adler;
-    const Bytef *buf;
-    uInt len;
+uLong ZEXPORT adler32(uLong adler, const Bytef *buf, uInt len)
 {
     unsigned long sum2;
     unsigned n;
diff --git a/lib/zlib/inffast.c b/lib/zlib/inffast.c
index 38f2f905e8..0700e04cb9 100644
--- a/lib/zlib/inffast.c
+++ b/lib/zlib/inffast.c
@@ -66,9 +66,8 @@
       requires strm->avail_out >= 258 for each loop to avoid checking for
       output space.
  */
-void inflate_fast(strm, start)
-z_streamp strm;
-unsigned start;         /* inflate()'s starting value for strm->avail_out */
+void inflate_fast(z_streamp strm, unsigned start)
+/* start: inflate()'s starting value for strm->avail_out */
 {
     struct inflate_state FAR *state;
     unsigned char FAR *in;      /* local strm->next_in */
diff --git a/lib/zlib/inflate.c b/lib/zlib/inflate.c
index 1eef609de5..6411c47932 100644
--- a/lib/zlib/inflate.c
+++ b/lib/zlib/inflate.c
@@ -5,8 +5,7 @@
 local void fixedtables OF((struct inflate_state FAR *state));
 local int updatewindow OF((z_streamp strm, unsigned out));
 
-int ZEXPORT inflateReset(strm)
-z_streamp strm;
+int ZEXPORT inflateReset(z_streamp strm)
 {
     struct inflate_state FAR *state;
 
@@ -31,11 +30,8 @@ z_streamp strm;
     return Z_OK;
 }
 
-int ZEXPORT inflateInit2_(strm, windowBits, version, stream_size)
-z_streamp strm;
-int windowBits;
-const char *version;
-int stream_size;
+int ZEXPORT inflateInit2_(z_streamp strm, int windowBits, const char *version,
+			  int stream_size)
 {
     struct inflate_state FAR *state;
 
@@ -74,16 +70,12 @@ int stream_size;
     return inflateReset(strm);
 }
 
-int ZEXPORT inflateInit_(strm, version, stream_size)
-z_streamp strm;
-const char *version;
-int stream_size;
+int ZEXPORT inflateInit_(z_streamp strm, const char *version, int stream_size)
 {
     return inflateInit2_(strm, DEF_WBITS, version, stream_size);
 }
 
-local void fixedtables(state)
-struct inflate_state FAR *state;
+local void fixedtables(struct inflate_state FAR *state)
 {
     state->lencode = lenfix;
     state->lenbits = 9;
@@ -105,9 +97,7 @@ struct inflate_state FAR *state;
    output will fall in the output data, making match copies simpler and faster.
    The advantage may be dependent on the size of the processor's data caches.
  */
-local int updatewindow(strm, out)
-z_streamp strm;
-unsigned out;
+local int updatewindow(z_streamp strm, unsigned out)
 {
     struct inflate_state FAR *state;
     unsigned copy, dist;
@@ -335,9 +325,7 @@ unsigned out;
    when flush is set to Z_FINISH, inflate() cannot return Z_OK.  Instead it
    will return Z_BUF_ERROR if it has not reached the end of the stream.
  */
-int ZEXPORT inflate(strm, flush)
-z_streamp strm;
-int flush;
+int ZEXPORT inflate(z_streamp strm, int flush)
 {
     struct inflate_state FAR *state;
     unsigned char FAR *next;    /* next input */
@@ -938,8 +926,7 @@ int flush;
     return ret;
 }
 
-int ZEXPORT inflateEnd(strm)
-z_streamp strm;
+int ZEXPORT inflateEnd(z_streamp strm)
 {
     struct inflate_state FAR *state;
     if (strm == Z_NULL || strm->state == Z_NULL || strm->zfree == (free_func)0)
diff --git a/lib/zlib/inftrees.c b/lib/zlib/inftrees.c
index c6d4c038dc..7474a52e7f 100644
--- a/lib/zlib/inftrees.c
+++ b/lib/zlib/inftrees.c
@@ -29,13 +29,9 @@
    table index bits.  It will differ if the request is greater than the
    longest code or if it is less than the shortest code.
  */
-int inflate_table(type, lens, codes, table, bits, work)
-codetype type;
-unsigned short FAR *lens;
-unsigned codes;
-code FAR * FAR *table;
-unsigned FAR *bits;
-unsigned short FAR *work;
+int inflate_table(codetype type, unsigned short FAR *lens, unsigned codes,
+		  code FAR * FAR *table, unsigned FAR *bits,
+		  unsigned short FAR *work)
 {
     unsigned len;               /* a code's length in bits */
     unsigned sym;               /* index of code symbols */
diff --git a/lib/zlib/zutil.c b/lib/zlib/zutil.c
index 65f9554747..14f6eb1e07 100644
--- a/lib/zlib/zutil.c
+++ b/lib/zlib/zutil.c
@@ -49,10 +49,7 @@ extern voidp    calloc OF((uInt items, uInt size));
 extern void     free   OF((voidpf ptr));
 #endif
 
-voidpf zcalloc (opaque, items, size)
-	voidpf opaque;
-	unsigned items;
-	unsigned size;
+voidpf zcalloc(voidpf opaque, unsigned items, unsigned size)
 {
 	if (opaque)
 		items += size - size; /* make compiler happy */
@@ -60,10 +57,7 @@ voidpf zcalloc (opaque, items, size)
 		(voidpf)calloc(items, size);
 }
 
-void  zcfree (opaque, ptr, nb)
-	voidpf opaque;
-	voidpf ptr;
-	unsigned nb;
+void  zcfree(voidpf opaque, voidpf ptr, unsigned nb)
 {
 	free(ptr);
 	if (opaque)