diff --git a/include/dbug.h b/include/dbug.h
index 3c86cbb8..be8238aa 100644
--- a/include/dbug.h
+++ b/include/dbug.h
@@ -38,8 +38,8 @@ extern	void _db_pargs_(uint _line_,const char *keyword);
 extern	void _db_doprnt_ _VARARGS((const char *format,...));
 extern	void _db_dump_(uint _line_,const char *keyword,const char *memory,
 		       uint length);
-extern	void _db_lock_file();
-extern	void _db_unlock_file();
+extern	void _db_lock_file(void);
+extern	void _db_unlock_file(void);
 
 #define DBUG_ENTER(a) const char *_db_func_, *_db_file_; uint _db_level_; \
 	char **_db_framep_; \
diff --git a/include/errmsg.h b/include/errmsg.h
index cea65583..300da39e 100644
--- a/include/errmsg.h
+++ b/include/errmsg.h
@@ -17,6 +17,8 @@
 
 /* Error messages for mysql clients */
 /* error messages for the demon is in share/language/errmsg.sys */
+#ifndef _errmsg_h_
+#define _errmsg_h_
 
 #ifdef	__cplusplus
 extern "C" {
@@ -74,3 +76,5 @@ extern const char *client_errors[];	/* Error messages */
 #define CR_PLUGIN_FUNCTION_NOT_SUPPORTED 2060
 
 #define SQLSTATE_UNKNOWN "HY000"
+
+#endif
diff --git a/include/m_ctype.h b/include/m_ctype.h
index cb2918d1..5022e2b1 100644
--- a/include/m_ctype.h
+++ b/include/m_ctype.h
@@ -58,7 +58,7 @@ CHARSET_INFO *find_compiled_charset_by_name(const char *name);
 
 size_t mysql_cset_escape_quotes(const CHARSET_INFO *cset, char *newstr,  const char *escapestr, size_t escapestr_len);
 size_t mysql_cset_escape_slashes(const CHARSET_INFO *cset, char *newstr, const char *escapestr, size_t escapestr_len);
-char* madb_get_os_character_set();
+char* madb_get_os_character_set(void);
 #ifdef _WIN32
 int madb_get_windows_cp(const char *charset);
 #endif
diff --git a/include/m_string.h b/include/m_string.h
index 9b94d51b..7d102127 100644
--- a/include/m_string.h
+++ b/include/m_string.h
@@ -88,9 +88,6 @@ extern "C" {
 
 #if defined(HAVE_STPCPY) && !defined(HAVE_mit_thread)
 #define strmov(A,B) stpcpy((A),(B))
-#ifndef stpcpy
-extern char *stpcpy(char *, const char *);	/* For AIX with gcc 2.95.3 */
-#endif
 #endif
 
 extern char NEAR _dig_vec[];		/* Declared in int2str() */
diff --git a/include/ma_secure.h b/include/ma_secure.h
index 46679376..f30e5d6a 100644
--- a/include/ma_secure.h
+++ b/include/ma_secure.h
@@ -37,7 +37,7 @@ SSL *my_ssl_init(MYSQL *mysql);
 int my_ssl_connect(SSL *ssl);
 
 int my_ssl_start(MYSQL *mysql);
-void my_ssl_end();
+void my_ssl_end(void);
 
 #endif /* HAVE_OPENSSL */
 #endif /* _ma_secure_h_ */
diff --git a/include/my_global.h b/include/my_global.h
index 4dda6459..1fa3ae12 100644
--- a/include/my_global.h
+++ b/include/my_global.h
@@ -347,7 +347,7 @@ typedef int	my_socket;	/* File descriptor for sockets */
 #endif
 /* Type for fuctions that handles signals */
 #define sig_handler RETSIGTYPE
-typedef void	(*sig_return)();/* Returns type from signal */
+typedef void	(*sig_return)(void);/* Returns type from signal */
 #if defined(__GNUC__) && !defined(_lint)
 typedef char	pchar;		/* Mixed prototypes can take char */
 typedef char	puchar;		/* Mixed prototypes can take char */
diff --git a/include/my_net.h b/include/my_net.h
index 89efc655..ef4c2927 100644
--- a/include/my_net.h
+++ b/include/my_net.h
@@ -34,8 +34,6 @@ extern "C" {
 #endif
 #endif /* !defined(MSDOS) && !defined(_WIN32) */
 
-void my_inet_ntoa(struct in_addr in, char *buf);
-
 /*
   Handling of gethostbyname_r()
 */
@@ -47,11 +45,8 @@ struct hostent;
 struct hostent *my_gethostbyname_r(const char *name,
 				   struct hostent *result, char *buffer,
 				   int buflen, int *h_errnop);
-void my_gethostbyname_r_free();
+void my_gethostbyname_r_free(void);
 #elif defined(HAVE_PTHREAD_ATTR_CREATE) || defined(_AIX) || defined(HAVE_GETHOSTBYNAME_R_GLIBC2_STYLE)
-struct hostent *my_gethostbyname_r(const char *name,
-				   struct hostent *result, char *buffer,
-				   int buflen, int *h_errnop);
 #define my_gethostbyname_r_free()
 #if !defined(HAVE_GETHOSTBYNAME_R_GLIBC2_STYLE) && !defined(HPUX)
 #define GETHOSTBYNAME_BUFF_SIZE sizeof(struct hostent_data)
diff --git a/include/my_stmt.h b/include/my_stmt.h
index 342b2612..2ea9c2a3 100644
--- a/include/my_stmt.h
+++ b/include/my_stmt.h
@@ -247,12 +247,4 @@ my_ulonglong STDCALL mysql_stmt_num_rows(MYSQL_STMT *stmt);
 my_ulonglong STDCALL mysql_stmt_affected_rows(MYSQL_STMT *stmt);
 my_ulonglong STDCALL mysql_stmt_insert_id(MYSQL_STMT *stmt);
 unsigned int STDCALL mysql_stmt_field_count(MYSQL_STMT *stmt);
-my_bool STDCALL mysql_stmt_reset(MYSQL_STMT *stmt);
-MYSQL_ROW_OFFSET STDCALL mysql_stmt_row_tell(MYSQL_STMT *stmt);
-MYSQL_ROW_OFFSET STDCALL mysql_stmt_row_seek(MYSQL_STMT *stmt, MYSQL_ROW_OFFSET new_row);
-unsigned long STDCALL mysql_stmt_param_count(MYSQL_STMT *stmt);
-my_bool STDCALL mysql_stmt_send_long_data(MYSQL_STMT *stmt, unsigned int param_number, const char *data, unsigned long length);
-my_ulonglong STDCALL mysql_stmt_insert_id(MYSQL_STMT *stmt);
-my_ulonglong STDCALL mysql_stmt_num_rows(MYSQL_STMT *stmt);
-MYSQL_RES* STDCALL mysql_stmt_param_metadata(MYSQL_STMT *stmt);
 int STDCALL mysql_stmt_next_result(MYSQL_STMT *stmt);
diff --git a/include/my_sys.h b/include/my_sys.h
index 0544848c..c6339890 100644
--- a/include/my_sys.h
+++ b/include/my_sys.h
@@ -178,11 +178,13 @@ void   __CDECL hfree(void *ptr);
 #endif
 #endif /* MSDOS */
 
+#ifndef errno
 #ifdef HAVE_ERRNO_AS_DEFINE
 #include <errno.h>			/* errno is a define */
 #else
 extern int errno;			/* declare errno */
 #endif
+#endif
 extern const char ** NEAR my_errmsg[];
 extern char NEAR errbuff[NRERRBUFFS][ERRMSGSIZE];
 extern char *home_dir;			/* Home directory for user */
diff --git a/include/mysql.h b/include/mysql.h
index 0f1bb818..ecce31e0 100644
--- a/include/mysql.h
+++ b/include/mysql.h
@@ -441,7 +441,7 @@ unsigned long STDCALL mysql_real_escape_string(MYSQL *mysql,
 					       unsigned long length);
 void		STDCALL mysql_debug(const char *debug);
 #define mysql_debug_init(A) mysql_debug((A));
-void            STDCALL mysql_debug_end();
+void    STDCALL mysql_debug_end(void);
 void 		STDCALL myodbc_remove_escape(MYSQL *mysql,char *name);
 unsigned int	STDCALL mysql_thread_safe(void);
 unsigned int STDCALL mysql_warning_count(MYSQL *mysql);
diff --git a/include/mysql/client_plugin.h b/include/mysql/client_plugin.h
index 5c06ada8..13970224 100644
--- a/include/mysql/client_plugin.h
+++ b/include/mysql/client_plugin.h
@@ -60,7 +60,7 @@
   const char *desc;                                     \
   unsigned int version[3];                              \
   int (*init)(char *, size_t, int, va_list);            \
-  int (*deinit)();
+  int (*deinit)(void);
 
 struct st_mysql_client_plugin
 {
diff --git a/include/mysql_com.h b/include/mysql_com.h
index 6d79c1ef..3eba8a84 100644
--- a/include/mysql_com.h
+++ b/include/mysql_com.h
@@ -374,7 +374,6 @@ void hash_password(unsigned long *result, const char *password, size_t len);
 
 /* Some other useful functions */
 
-void my_init(void);
 void load_defaults(const char *conf_file, const char **groups,
 		   int *argc, char ***argv);
 my_bool my_thread_init(void);