diff --git a/contrib/minizip/crypt.h b/contrib/minizip/crypt.h
index 1e9e820..131543f 100644
--- a/contrib/minizip/crypt.h
+++ b/contrib/minizip/crypt.h
@@ -38,6 +38,7 @@
                      * unpredictable manner on 16-bit systems; not a problem
                      * with any known compiler so far, though */
 
+    (void)pcrc_32_tab;
     temp = ((unsigned)(*(pkeys+2)) & 0xffff) | 2;
     return (int)(((temp * (temp ^ 1)) >> 8) & 0xff);
 }
diff --git a/contrib/minizip/ioapi.c b/contrib/minizip/ioapi.c
index 7f5c191..1571914 100644
--- a/contrib/minizip/ioapi.c
+++ b/contrib/minizip/ioapi.c
@@ -94,6 +94,7 @@
 
 static voidpf ZCALLBACK fopen_file_func (voidpf opaque, const char* filename, int mode)
 {
+    (void)opaque;
     FILE* file = NULL;
     const char* mode_fopen = NULL;
     if ((mode & ZLIB_FILEFUNC_MODE_READWRITEFILTER)==ZLIB_FILEFUNC_MODE_READ)
@@ -112,6 +113,7 @@
 
 static voidpf ZCALLBACK fopen64_file_func (voidpf opaque, const void* filename, int mode)
 {
+    (void)opaque;
     FILE* file = NULL;
     const char* mode_fopen = NULL;
     if ((mode & ZLIB_FILEFUNC_MODE_READWRITEFILTER)==ZLIB_FILEFUNC_MODE_READ)
@@ -131,6 +133,7 @@
 
 static uLong ZCALLBACK fread_file_func (voidpf opaque, voidpf stream, void* buf, uLong size)
 {
+    (void)opaque;
     uLong ret;
     ret = (uLong)fread(buf, 1, (size_t)size, (FILE *)stream);
     return ret;
@@ -138,6 +141,7 @@
 
 static uLong ZCALLBACK fwrite_file_func (voidpf opaque, voidpf stream, const void* buf, uLong size)
 {
+    (void)opaque;
     uLong ret;
     ret = (uLong)fwrite(buf, 1, (size_t)size, (FILE *)stream);
     return ret;
@@ -145,6 +149,7 @@
 
 static long ZCALLBACK ftell_file_func (voidpf opaque, voidpf stream)
 {
+    (void)opaque;
     long ret;
     ret = ftell((FILE *)stream);
     return ret;
@@ -153,6 +158,7 @@
 
 static ZPOS64_T ZCALLBACK ftell64_file_func (voidpf opaque, voidpf stream)
 {
+    (void)opaque;
     ZPOS64_T ret;
     ret = FTELLO_FUNC((FILE *)stream);
     return ret;
@@ -160,6 +166,7 @@
 
 static long ZCALLBACK fseek_file_func (voidpf  opaque, voidpf stream, uLong offset, int origin)
 {
+    (void)opaque;
     int fseek_origin=0;
     long ret;
     switch (origin)
@@ -183,6 +190,7 @@
 
 static long ZCALLBACK fseek64_file_func (voidpf  opaque, voidpf stream, ZPOS64_T offset, int origin)
 {
+    (void)opaque;
     int fseek_origin=0;
     long ret;
     switch (origin)
@@ -209,6 +217,7 @@
 
 static int ZCALLBACK fclose_file_func (voidpf opaque, voidpf stream)
 {
+    (void)opaque;
     int ret;
     ret = fclose((FILE *)stream);
     return ret;
@@ -216,6 +225,7 @@
 
 static int ZCALLBACK ferror_file_func (voidpf opaque, voidpf stream)
 {
+    (void)opaque;
     int ret;
     ret = ferror((FILE *)stream);
     return ret;
diff --git a/contrib/minizip/miniunz.c b/contrib/minizip/miniunz.c
index 3d65401..8e34bd9 100644
--- a/contrib/minizip/miniunz.c
+++ b/contrib/minizip/miniunz.c
@@ -45,6 +45,7 @@
 #include <time.h>
 #include <errno.h>
 #include <fcntl.h>
+#include <sys/stat.h>
 
 #ifdef _WIN32
 # include <direct.h>
@@ -97,7 +98,8 @@
   SetFileTime(hFile,&ftm,&ftLastAcc,&ftm);
   CloseHandle(hFile);
 #else
-#ifdef unix || __APPLE__
+#if defined(unix) || defined(__APPLE__)
+  (void)dosdate;
   struct utimbuf ut;
   struct tm newdate;
   newdate.tm_sec = tmu_date.tm_sec;
@@ -136,7 +138,7 @@
 }
 
 int makedir (newdir)
-    char *newdir;
+    const char *newdir;
 {
   char *buffer ;
   char *p;
@@ -324,7 +326,6 @@
     uInt size_buf;
 
     unz_file_info64 file_info;
-    uLong ratio=0;
     err = unzGetCurrentFileInfo64(uf,&file_info,filename_inzip,sizeof(filename_inzip),NULL,0,NULL,0);
 
     if (err!=UNZ_OK)
@@ -481,7 +482,6 @@
     uLong i;
     unz_global_info64 gi;
     int err;
-    FILE* fout=NULL;
 
     err = unzGetGlobalInfo64(uf,&gi);
     if (err!=UNZ_OK)
@@ -515,7 +515,6 @@
     int opt_overwrite;
     const char* password;
 {
-    int err = UNZ_OK;
     if (unzLocateFile(uf,filename,CASESENSITIVITY)!=UNZ_OK)
     {
         printf("file %s not found in the zipfile\n",filename);
diff --git a/contrib/minizip/minizip.c b/contrib/minizip/minizip.c
index 4288962..2a38549 100644
--- a/contrib/minizip/minizip.c
+++ b/contrib/minizip/minizip.c
@@ -72,7 +72,7 @@
 
 #ifdef _WIN32
 uLong filetime(f, tmzip, dt)
-    char *f;                /* name of file to get info on */
+    const char *f;          /* name of file to get info on */
     tm_zip *tmzip;             /* return value: access, modific. and creation times */
     uLong *dt;             /* dostime */
 {
@@ -94,12 +94,13 @@
   return ret;
 }
 #else
-#ifdef unix || __APPLE__
+#if defined(unix) || defined(__APPLE__)
 uLong filetime(f, tmzip, dt)
-    char *f;               /* name of file to get info on */
+    const char *f;         /* name of file to get info on */
     tm_zip *tmzip;         /* return value: access, modific. and creation times */
     uLong *dt;             /* dostime */
 {
+  (void)dt;
   int ret=0;
   struct stat s;        /* results of stat() */
   struct tm* filedate;
@@ -138,7 +139,7 @@
 }
 #else
 uLong filetime(f, tmzip, dt)
-    char *f;                /* name of file to get info on */
+    const char *f;          /* name of file to get info on */
     tm_zip *tmzip;             /* return value: access, modific. and creation times */
     uLong *dt;             /* dostime */
 {
@@ -229,7 +230,7 @@
 
   if(pFile != NULL)
   {
-    int n = FSEEKO_FUNC(pFile, 0, SEEK_END);
+    FSEEKO_FUNC(pFile, 0, SEEK_END);
     pos = FTELLO_FUNC(pFile);
 
                 printf("File : %s is %lld bytes\n", filename, pos);