diff --git a/cookie.c b/cookie.c
index 705e277..0a6aecf 100644
--- a/cookie.c
+++ b/cookie.c
@@ -191,7 +191,7 @@ match_cookie(ParsedURL *pu, struct cookie *cookie, char *domainname)
     return 1;
 }
 
-struct cookie *
+static struct cookie *
 get_cookie_info(Str domain, Str path, Str name)
 {
     struct cookie *p;
@@ -254,7 +254,7 @@ find_cookie(ParsedURL *pu)
     return tmp;
 }
 
-int
+static int
 check_avoid_wrong_number_of_dots_domain( Str domain )
 {
    TextListItem *tl;
@@ -412,7 +412,7 @@ add_cookie(ParsedURL *pu, Str name, Str value,
     return 0;
 }
 
-struct cookie *
+static struct cookie *
 nth_cookie(int n)
 {
     struct cookie *p;
diff --git a/entity.c b/entity.c
index 67b8cfb..acb593f 100644
--- a/entity.c
+++ b/entity.c
@@ -14,6 +14,8 @@
 #endif
 #endif				/* DUMMY */
 
+extern char * conv_entity(unsigned int c);
+
 /* *INDENT-OFF* */
 static char *alt_latin1[ 96 ] = {
     NBSP,  "!",   "-c-", "-L-", "CUR", "=Y=",  "|",  "S:",
diff --git a/file.c b/file.c
index 9704cea..371ca97 100644
--- a/file.c
+++ b/file.c
@@ -418,7 +418,7 @@ examineFile(char *path, URLFile *uf)
 
 #define S_IXANY	(S_IXUSR|S_IXGRP|S_IXOTH)
 
-int
+static int
 check_command(char *cmd, int auxbin_p)
 {
     static char *path = NULL;
@@ -449,7 +449,7 @@ check_command(char *cmd, int auxbin_p)
 }
 
 char *
-acceptableEncoding()
+acceptableEncoding(void)
 {
     static Str encodings = NULL;
     struct compression_decoder *d;
@@ -938,7 +938,7 @@ checkHeader(Buffer *buf, char *field)
     return NULL;
 }
 
-char *
+static char *
 checkContentType(Buffer *buf)
 {
     char *p;
@@ -2750,7 +2750,7 @@ is_blank_line(char *line, int indent)
 }
 #endif
 
-void
+static void
 fillline(struct readbuffer *obuf, int indent)
 {
     push_spaces(obuf, 1, indent - obuf->pos);
@@ -4148,7 +4148,7 @@ feed_textarea(char *str)
     }
 }
 
-Str
+static Str
 process_hr(struct parsed_tag *tag, int width, int indent_width)
 {
     Str tmp = Strnew_charp("<nobr>");
@@ -5547,7 +5547,7 @@ HTMLtagproc1(struct parsed_tag *tag, struct html_feed_environ *h_env)
 static TextLineListItem *_tl_lp2;
 
 static Str
-textlist_feed()
+textlist_feed(void)
 {
     TextLine *p;
     if (_tl_lp2 != NULL) {
@@ -6330,7 +6330,7 @@ HTMLlineproc2(Buffer *buf, TextLineList *tl)
 static InputStream _file_lp2;
 
 static Str
-file_feed()
+file_feed(void)
 {
     Str s;
     s = StrISgets(_file_lp2);
@@ -6341,7 +6341,7 @@ file_feed()
     return s;
 }
 
-void
+static void
 HTMLlineproc3(Buffer *buf, InputStream stream)
 {
     _file_lp2 = stream;
diff --git a/frame.c b/frame.c
index be1a961..6369cdc 100644
--- a/frame.c
+++ b/frame.c
@@ -210,7 +210,7 @@ copyFrameSet(struct frameset *of)
     return rf;
 }
 
-void
+static void
 flushFrameSet(struct frameset *fs)
 {
     int n = fs->i;
diff --git a/func.c b/func.c
index 8b5deac..c229799 100644
--- a/func.c
+++ b/func.c
@@ -9,6 +9,7 @@
 #include "func.h"
 #include "myctype.h"
 #include "regex.h"
+#include "rc.h"
 
 #include "funcname.c"
 #include "functable.c"
diff --git a/history.c b/history.c
index eeb8f5c..514ae9a 100644
--- a/history.c
+++ b/history.c
@@ -89,7 +89,7 @@ saveHistory(Hist *hist, size_t size)
 #endif				/* USE_HISTORY */
 
 Hist *
-newHist()
+newHist(void)
 {
     Hist *hist;
 
diff --git a/history.h b/history.h
index e2b3bf2..a6468ec 100644
--- a/history.h
+++ b/history.h
@@ -18,7 +18,7 @@ typedef struct {
     Hash_sv *hash;
 } Hist;
 
-extern Hist *newHist();
+extern Hist *newHist(void);
 extern Hist *copyHist(Hist *hist);
 extern HistItem *unshiftHist(Hist *hist, char *ptr);
 extern HistItem *pushHist(Hist *hist, char *ptr);
diff --git a/image.c b/image.c
index 3532040..6570cb4 100644
--- a/image.c
+++ b/image.c
@@ -31,9 +31,9 @@ static int n_terminal_image = 0;
 static int max_terminal_image = 0;
 static FILE *Imgdisplay_rf = NULL, *Imgdisplay_wf = NULL;
 static pid_t Imgdisplay_pid = 0;
-static int openImgdisplay();
-static void closeImgdisplay();
-int getCharSize();
+static int openImgdisplay(void);
+static void closeImgdisplay(void);
+static int getCharSize(void);
 
 void
 initImage()
@@ -46,8 +46,8 @@ initImage()
 
 int get_pixel_per_cell(int *ppc, int *ppl);
 
-int
-getCharSize()
+static int
+getCharSize(void)
 {
     FILE *f;
     Str tmp;
@@ -134,7 +134,7 @@ openImgdisplay()
 }
 
 static void
-closeImgdisplay()
+closeImgdisplay(void)
 {
     if (Imgdisplay_wf)
 	fclose(Imgdisplay_wf);
@@ -195,14 +195,8 @@ syncImage(void)
     n_terminal_image = 0;
 }
 
-void put_image_osc5379(char *url, int x, int y, int w, int h, int sx, int sy, int sw, int sh);
-void put_image_sixel(char *url, int x, int y, int w, int h, int sx, int sy, int sw, int sh, int n_terminal_image);
-void put_image_iterm2(char *url, int x, int y, int w, int h);
-void put_image_kitty(char *url, int x, int y, int w, int h, int sx, int sy, int
-    sw, int sh, int c, int r);
-
 void
-drawImage()
+drawImage(void)
 {
     static char buf[64];
     int j, draw = FALSE;
@@ -388,7 +382,7 @@ getAllImage(Buffer *buf)
     }
 }
 
-void
+static void
 showImageProgress(Buffer *buf)
 {
     AnchorList *al;
diff --git a/indep.c b/indep.c
index 4d13a3f..d9b9ae9 100644
--- a/indep.c
+++ b/indep.c
@@ -840,32 +840,32 @@ w3m_dir(const char *name, char *dft)
 }
 
 char *
-w3m_auxbin_dir()
+w3m_auxbin_dir(void)
 {
     return w3m_dir("W3M_AUXBIN_DIR", AUXBIN_DIR);
 }
 
 char *
-w3m_lib_dir()
+w3m_lib_dir(void)
 {
     /* FIXME: use W3M_CGIBIN_DIR? */
     return w3m_dir("W3M_LIB_DIR", CGIBIN_DIR);
 }
 
 char *
-w3m_etc_dir()
+w3m_etc_dir(void)
 {
     return w3m_dir("W3M_ETC_DIR", ETC_DIR);
 }
 
 char *
-w3m_conf_dir()
+w3m_conf_dir(void)
 {
     return w3m_dir("W3M_CONF_DIR", CONF_DIR);
 }
 
 char *
-w3m_help_dir()
+w3m_help_dir(void)
 {
     return w3m_dir("W3M_HELP_DIR", HELP_DIR);
 }
diff --git a/indep.h b/indep.h
index b123c85..d4bef53 100644
--- a/indep.h
+++ b/indep.h
@@ -86,11 +86,11 @@ extern void growbuf_reserve(struct growbuf *gb, int leastarea);
 extern void growbuf_append(struct growbuf *gb, const unsigned char *src, int len);
 #define GROWBUF_ADD_CHAR(gb,ch) ((((gb)->length>=(gb)->area_size)?growbuf_reserve(gb,(gb)->length+1):(void)0),(void)((gb)->ptr[(gb)->length++] = (ch)))
 
-extern char *w3m_auxbin_dir();
-extern char *w3m_lib_dir();
-extern char *w3m_etc_dir();
-extern char *w3m_conf_dir();
-extern char *w3m_help_dir();
+extern char *w3m_auxbin_dir(void);
+extern char *w3m_lib_dir(void);
+extern char *w3m_etc_dir(void);
+extern char *w3m_conf_dir(void);
+extern char *w3m_help_dir(void);
 
 #define NewWithoutGC(type)	((type*)xmalloc(sizeof(type)))
 #define NewWithoutGC_N(type,n)	((type*)xmalloc((n)*sizeof(type)))
diff --git a/linein.c b/linein.c
index b58cad6..9da03ad 100644
--- a/linein.c
+++ b/linein.c
@@ -845,7 +845,7 @@ next_dcompl(int next)
 }
 
 
-Str
+static Str
 escape_spaces(Str s)
 {
     Str tmp = NULL;
diff --git a/mailcap.c b/mailcap.c
index f0c6242..cca13f9 100644
--- a/mailcap.c
+++ b/mailcap.c
@@ -220,7 +220,7 @@ loadMailcap(char *filename)
 }
 
 void
-initMailcap()
+initMailcap(void)
 {
     TextListItem *tl;
     int i;
@@ -238,7 +238,7 @@ initMailcap()
 }
 
 char *
-acceptableMimeTypes()
+acceptableMimeTypes(void)
 {
     static Str types = NULL;
     TextList *l;
@@ -308,7 +308,7 @@ searchExtViewer(char *type)
 #define MCF_SQUOTED (1 << 0)
 #define MCF_DQUOTED (1 << 1)
 
-Str
+static Str
 quote_mailcap(char *s, int flag)
 {
     Str d;
diff --git a/main.c b/main.c
index 45f5a4b..7873a5a 100644
--- a/main.c
+++ b/main.c
@@ -18,6 +18,7 @@
 #include "terms.h"
 #include "myctype.h"
 #include "regex.h"
+#include "rc.h"
 #ifdef USE_M17N
 #include "wc.h"
 #include "wtf.h"
@@ -363,7 +364,7 @@ sig_chld(int signo)
 }
 #endif
 
-Str
+static Str
 make_optional_header_string(char *s)
 {
     char *p;
@@ -1886,7 +1887,7 @@ dispincsrch(int ch, Str buf, Lineprop *prop)
     return -1;
 }
 
-void
+static void
 isrch(int (*func) (Buffer *, char *), char *prompt)
 {
     char *str;
@@ -1902,7 +1903,7 @@ isrch(int (*func) (Buffer *, char *), char *prompt)
     displayBuffer(Currentbuf, B_FORCE_REDRAW);
 }
 
-void
+static void
 srch(int (*func) (Buffer *, char *), char *prompt)
 {
     char *str;
diff --git a/proto.h b/proto.h
index be9d64a..3be7d22 100644
--- a/proto.h
+++ b/proto.h
@@ -164,7 +164,7 @@ extern int currentLn(Buffer *buf);
 extern void tmpClearBuffer(Buffer *buf);
 extern char *filename_extension(char *patch, int is_url);
 #ifdef USE_EXTERNAL_URI_LOADER
-extern void initURIMethods();
+extern void initURIMethods(void);
 extern Str searchURIMethods(ParsedURL *pu);
 extern void chkExternalURIBuffer(Buffer *buf);
 #endif
@@ -188,7 +188,7 @@ extern char *url_decode0(const char *url);
 #define url_decode2(url, buf) url_decode0(url)
 #endif /* !defined(USE_M17N) */
 extern void examineFile(char *path, URLFile *uf);
-extern char *acceptableEncoding();
+extern char *acceptableEncoding(void);
 extern int dir_exist(char *path);
 extern int is_html_type(char *type);
 #ifdef USE_M17N
@@ -533,10 +533,10 @@ extern char getch(void);
 extern void bell(void);
 extern int sleep_till_anykey(int sec, int purge);
 #ifdef USE_IMAGE
-extern void touch_cursor();
+extern void touch_cursor(void);
 #endif
-extern void initMimeTypes();
-extern void free_ssl_ctx();
+extern void initMimeTypes(void);
+extern void free_ssl_ctx(void);
 extern ParsedURL *baseURL(Buffer *buf);
 extern int openSocket(char *hostname, char *remoteport_name,
 		      unsigned short remoteport_num);
@@ -555,8 +555,8 @@ extern URLFile openURL(char *url, ParsedURL *pu, ParsedURL *current,
 		       HRequest *hr, unsigned char *status);
 extern int mailcapMatch(struct mailcap *mcap, char *type);
 extern struct mailcap *searchMailcap(struct mailcap *table, char *type);
-extern void initMailcap();
-extern char *acceptableMimeTypes();
+extern void initMailcap(void);
+extern char *acceptableMimeTypes(void);
 extern struct mailcap *searchExtViewer(char *type);
 extern Str unquote_mailcap(char *qstr, char *type, char *name, char *attr,
 			   int *mc_stat);
diff --git a/rc.c b/rc.c
index 5511e25..d335564 100644
--- a/rc.c
+++ b/rc.c
@@ -12,6 +12,7 @@
 #include "regex.h"
 #include <stdlib.h>
 #include <stddef.h>
+#include "rc.h"
 
 struct param_ptr {
     char *name;
@@ -852,7 +853,7 @@ create_option_search_table()
     }
 }
 
-struct param_ptr *
+static struct param_ptr *
 search_param(char *name)
 {
     size_t b, e, i;
@@ -1182,8 +1183,8 @@ interpret_rc(FILE * f)
     }
 }
 
-void
-parse_proxy()
+static void
+parse_proxy(void)
 {
     if (non_null(HTTP_proxy))
 	parseURL(HTTP_proxy, &HTTP_proxy_parsed, NULL);
@@ -1202,8 +1203,8 @@ parse_proxy()
 }
 
 #ifdef USE_COOKIE
-void
-parse_cookie()
+static void
+parse_cookie(void)
 {
     if (non_null(cookie_reject_domains))
 	Cookie_reject_domains = make_domain_list(cookie_reject_domains);
diff --git a/rc.h b/rc.h
new file mode 100644
index 0000000..edb1821
--- /dev/null
+++ b/rc.h
@@ -0,0 +1,7 @@
+#ifndef RC_H
+#define RC_H
+
+extern void show_params(FILE * fp);
+extern int str_to_bool(char *value, int old);
+
+#endif /* RC_H */
diff --git a/table.c b/table.c
index 9d99bb3..043df86 100644
--- a/table.c
+++ b/table.c
@@ -404,7 +404,7 @@ pushdata(struct table *t, int row, int col, char *data)
     pushText(t->tabdata[row][col], data ? data : "");
 }
 
-void
+static void
 suspend_or_pushdata(struct table *tbl, char *line)
 {
     if (tbl->flag & TBL_IN_COL)
@@ -509,7 +509,7 @@ visible_length(char *str)
     return len > max_len ? len : max_len;
 }
 
-int
+static int
 visible_length_plain(char *str)
 {
     int len = 0, max_len = 0;
@@ -922,7 +922,7 @@ check_cell_width(short *tabwidth, short *cellwidth,
     }
 }
 
-void
+static void
 check_minimum_width(struct table *t, short *tabwidth)
 {
     int i;
@@ -937,7 +937,7 @@ check_minimum_width(struct table *t, short *tabwidth)
 		     cell->maxcell, cell->index, t->cellspacing, 0);
 }
 
-void
+static void
 check_maximum_width(struct table *t)
 {
     struct table_cell *cell = &t->cell;
@@ -1255,7 +1255,7 @@ check_compressible_cell(struct table *t, MAT * minv,
 }
 
 #define MAX_ITERATION 10
-int
+static int
 check_table_width(struct table *t, double *newwidth, MAT * minv, int itr)
 {
     int i, j, k, m, bcol, ecol;
@@ -1513,7 +1513,7 @@ set_table_width(struct table *t, short *newwidth, int maxwidth)
 }
 #endif				/* not MATRIX */
 
-void
+static void
 check_table_height(struct table *t)
 {
     int i, j, k;
@@ -1612,7 +1612,7 @@ check_table_height(struct table *t)
 #define CHECK_MINIMUM	1
 #define CHECK_FIXED	2
 
-int
+static int
 get_table_width(struct table *t, short *orgwidth, short *cellwidth, int flag)
 {
 #ifdef __GNUC__
@@ -1677,7 +1677,7 @@ initRenderTable(void)
     cotable_level = 0;
 }
 
-void
+static void
 renderCoTable(struct table *tbl, int maxlimit)
 {
     struct readbuffer obuf;
@@ -2289,7 +2289,7 @@ check_rowcol(struct table *tbl, struct table_mode *mode)
     tbl->flag |= TBL_IN_COL;
 }
 
-int
+static int
 skip_space(struct table *t, char *line, struct table_linfo *linfo,
 	   int checkminimum)
 {
@@ -3585,7 +3585,7 @@ set_table_matrix0(struct table *t, int maxwidth)
     }
 }
 
-void
+static void
 check_relative_width(struct table *t, int maxwidth)
 {
     int i;
diff --git a/terms.c b/terms.c
index e272aab..ad6df34 100644
--- a/terms.c
+++ b/terms.c
@@ -41,7 +41,7 @@ static int xpix, ypix, nbs, obs = 0;
 
 static int is_xterm = 0;
 
-void mouse_init(), mouse_end();
+void mouse_init(void), mouse_end(void);
 int mouseActive = 0;
 #endif				/* USE_MOUSE */
 
@@ -263,7 +263,7 @@ check_cygwin_console(void)
 char *getenv(const char *);
 MySignalHandler reset_exit(SIGNAL_ARG), reset_error_exit(SIGNAL_ARG), error_dump(SIGNAL_ARG);
 void setlinescols(void);
-void flush_tty();
+void flush_tty(void);
 
 #ifndef SIGIOT
 #define SIGIOT SIGABRT
@@ -452,7 +452,7 @@ extern int tgetflag(char *);
 extern char *tgetstr(char *, char **);
 extern char *tgoto(char *, int, int);
 extern int tputs(char *, int, int (*)(char));
-void clear(), wrap(), touch_line(), touch_column(int);
+void clear(void), wrap(void), touch_line(void), touch_column(int);
 #if 0
 void need_clrtoeol(void);
 #endif
@@ -2059,7 +2059,7 @@ clrtoeol(void)
 }
 
 #ifdef USE_BG_COLOR
-void
+static void
 clrtoeol_with_bcolor(void)
 {
     int i, cli, cco;
@@ -2093,7 +2093,7 @@ clrtoeolx(void)
 }
 #endif				/* not USE_BG_COLOR */
 
-void
+static void
 clrtobot_eol(void (*clrtoeol) ())
 {
     int l, c;
@@ -2422,7 +2422,7 @@ bell(void)
     write1(7);
 }
 
-void
+static void
 skip_escseq(void)
 {
     int c;
@@ -2654,7 +2654,7 @@ mouse_inactive()
 #endif				/* USE_MOUSE */
 
 void
-flush_tty()
+flush_tty(void)
 {
     if (ttyf)
 	fflush(ttyf);
@@ -2662,7 +2662,7 @@ flush_tty()
 
 #ifdef USE_IMAGE
 void
-touch_cursor()
+touch_cursor(void)
 {
 #ifdef USE_M17N
     int i;
diff --git a/terms.h b/terms.h
index 55c7a60..8c6992e 100644
--- a/terms.h
+++ b/terms.h
@@ -30,4 +30,12 @@ extern void disable_win9x_console_input(void);
 #endif
 #endif
 
+#ifdef USE_IMAGE
+extern void put_image_osc5379(char *url, int x, int y, int w, int h, int sx, int sy, int sw, int sh);
+extern void put_image_sixel(char *url, int x, int y, int w, int h, int sx, int sy, int sw, int sh, int n_terminal_image);
+extern void put_image_iterm2(char *url, int x, int y, int w, int h);
+extern void put_image_kitty(char *url, int x, int y, int w, int h, int sx, int sy, int sw, int sh, int c, int r);
+extern int get_pixel_per_cell(int *ppc, int *ppl);
+#endif
+
 #endif				/* not TERMS_H */
diff --git a/url.c b/url.c
index 07f3ea0..b4c9ce4 100644
--- a/url.c
+++ b/url.c
@@ -202,7 +202,7 @@ loadMimeTypes(char *filename)
 }
 
 void
-initMimeTypes()
+initMimeTypes(void)
 {
     int i;
     TextListItem *tl;
@@ -251,7 +251,7 @@ KeyAbort(SIGNAL_ARG)
 SSL_CTX *ssl_ctx = NULL;
 
 void
-free_ssl_ctx()
+free_ssl_ctx(void)
 {
     if (ssl_ctx != NULL)
 	SSL_CTX_free(ssl_ctx);
@@ -262,7 +262,7 @@ free_ssl_ctx()
 #if SSLEAY_VERSION_NUMBER >= 0x00905100
 #include <openssl/rand.h>
 static void
-init_PRNG()
+init_PRNG(void)
 {
     char buffer[256];
     const char *file;
@@ -2305,7 +2305,7 @@ loadURIMethods(char *filename)
 }
 
 void
-initURIMethods()
+initURIMethods(void)
 {
     TextList *methodmap_list = NULL;
     TextListItem *tl;
diff --git a/w3mbookmark.c b/w3mbookmark.c
index 2e64327..bf3dade 100644
--- a/w3mbookmark.c
+++ b/w3mbookmark.c
@@ -51,7 +51,7 @@ static char end_section[] =
 
 static char *Local_cookie = NULL;
 
-void
+static void
 print_bookmark_panel(char *bmark, char *url, char *title, char *charset)
 {
     Str tmp, tmp2;
@@ -107,7 +107,7 @@ create_new_bookmark(char *bmark, char *section, char *title, char *url,
     return TRUE;
 }
 
-int
+static int
 insert_bookmark(char *bmark, struct parsed_tagarg *data)
 {
     char *url, *title, *section;
diff --git a/w3mhelperpanel.c b/w3mhelperpanel.c
index 7d13032..a519954 100644
--- a/w3mhelperpanel.c
+++ b/w3mhelperpanel.c
@@ -29,9 +29,9 @@
 #define MSG_DOIT		"Do it"
 #endif				/* LANG != JA */
 
-char *local_cookie;
+static char *local_cookie;
 
-void
+static void
 extractMailcapEntry(char *mcap_entry, char **type, char **cmd)
 {
     int j;
@@ -56,7 +56,7 @@ bye(const char *action, const char *mailcap)
     exit(1);
 }
 
-void
+static void
 printMailcapPanel(char *mailcap)
 {
     FILE *f;
@@ -118,7 +118,7 @@ printMailcapPanel(char *mailcap)
     fclose(f);
 }
 
-void
+static void
 editMailcap(char *mailcap, struct parsed_tagarg *args)
 {
     TextList *t = newTextList();