Supply prototypes where possible. This uncovered type errors with

thread entrypoints:
(lwpSelect, shutdown_sequence): Parameters didn't match thread entry
point prototype.
(lwpEntryPoint): Arguments didn't match thread entry point prototype.

Change linkage of functions without prototype declaration to static
where possible.

Remove some superflous declarations, replace others by suitable
includes.

src/lib/commands/anti.c

@@ -67,7 +67,6 @@ anti(void)
     double odds, damil, dache;
     int mob;
     int n_cheleft;
-    extern double hap_fact();
 
     if (!snxtsct(&nstr, player->argp[1]))
 	return RET_SYN;

src/lib/commands/best.c

@@ -48,7 +48,7 @@ int
 best(void)
 {
     double cost;
-    s_char *BestDistPath(), *BestLandPath(), *s;
+    s_char *s;
     struct sctstr s1, s2;
     struct nstr_sect nstr, nstr2;
     s_char buf[1024];

src/lib/commands/bomb.c

@@ -214,7 +214,6 @@ bomb(void)
 static void
 pin_bomb(struct emp_qelem *list, struct sctstr *target)
 {
-    extern s_char *effadv();
     struct dchrstr *dcp;
     int nplanes;
     int nships;

src/lib/commands/budg.c

@@ -348,7 +348,6 @@ calc_all(long int (*p_sect)[2], int *taxes, int *Ncivs, int *Nuws,
     extern long lnd_money[MAXNOC];
     extern long air_money[MAXNOC];
     extern long tpops[MAXNOC];
-    extern int mil_dbl_pay;
 
     lnd_money[player->cnum] = sea_money[player->cnum] = 0;
     air_money[player->cnum] = 0;

src/lib/commands/buil.c

@@ -31,6 +31,7 @@
  *      Steve McClure, 1998-2000
  */
 
+#include <math.h>
 #ifdef Rel4
 #include <string.h>
 #endif /* Rel4 */
@@ -69,9 +70,6 @@ static int build_plane(register struct sctstr *sp,
 
 static int cash;		/* static ok */
 
-double sqrt(double);
-double logx();
-
 extern int morale_base;
 extern int sect_mob_neg_factor;
 extern int etu_per_update;
@@ -494,7 +492,6 @@ build_land(register struct sctstr *sp, register struct lchrstr *lp,
     int points;
     struct natstr *natp;
     float eff = ((float)LAND_MINEFF / 100.0);
-    double techfact(int, double);
     int mil, lcm, hcm, gun, shell;
     int freeland = 0;
 

src/lib/commands/cons.c

@@ -111,9 +111,7 @@ static int
 cons_choose(struct ltcomstr *ltcp)
 {
     s_char *p;
-    extern int disloan();
-    extern int distrea();
-    int (*dis) ();
+    int (*dis)();
     struct lonstr *lp;
     struct trtstr *tp;
     s_char prompt[128];

src/lib/commands/desi.c

@@ -71,8 +71,6 @@ static long
 do_desi(struct natstr *natp, s_char *sects, s_char *deschar, long int cash,
 	int for_real)
 {
-    extern int opt_NO_LCMS;
-    extern int opt_NO_HCMS;
     register int n;
     s_char *p;
     int breaksanct;

src/lib/commands/diss.c

@@ -53,7 +53,6 @@
 int
 diss(void)
 {
-    int quit(void);
     struct sctstr sect;
     struct lndstr land;
     struct shpstr ship;

src/lib/commands/land.c

@@ -51,7 +51,6 @@ land(void)
     struct nstr_item ni;
     struct lndstr land;
     int vec[I_MAX + 1];
-    s_char *mission_short_name();
 
     if (!snxtitem(&ni, EF_LAND, player->argp[1]))
 	return RET_SYN;

src/lib/commands/ldump.c

@@ -53,7 +53,7 @@ ldump(void)
     struct nstr_item ni;
     struct lndstr land;
     int vec[I_MAX + 1];
-    s_char *mission_short_name();
+    s_char *mission_short_name(int);
     int n, i;
     struct natstr *np;
     time_t now;

src/lib/commands/look.c

@@ -257,7 +257,6 @@ look_land(register struct lndstr *lookland)
     int vrange;
     int i;
     int dist;
-    double techfact(int, double);
 
     drange = techfact(lookland->lnd_tech, (double)lookland->lnd_spy);
     drange = (drange * ((double)lookland->lnd_effic / 100.0));

src/lib/commands/lstat.c

@@ -50,7 +50,7 @@ lsta(void)
     int nunits;
     struct nstr_item ni;
     struct lndstr land;
-    s_char *mission_short_name();
+    s_char *mission_short_name(int);
 
     if (!snxtitem(&ni, EF_LAND, player->argp[1]))
 	return RET_SYN;

src/lib/commands/mark.c

@@ -57,7 +57,7 @@ mark(void)
 	return display_mark("   ");
 }
 
-void
+static void
 pr_mark(struct comstr *comm)
 {
     time_t now;

src/lib/commands/mfir.c

@@ -780,7 +780,6 @@ quiet_bigdef(int attacker, struct emp_qelem *list, natid own, natid aown,
     struct sctstr firing;
     struct nstr_sect ns;
     struct flist *fp;
-    double techfact(int, double);
     extern int torpedo_damage;
     int gun;
 

src/lib/commands/miss.c

@@ -71,7 +71,6 @@ mission(void)
     extern int land_mob_max;
     extern int plane_mob_max;
     extern double mission_mob_cost;
-    s_char *nameofitem();
     s_char prompt[128];
     s_char buf[1024];
 

src/lib/commands/mora.c

@@ -53,7 +53,6 @@ morale(void)
     int i, min;
     s_char *p;
     s_char mess[128];
-    double techfact(int, double);
     s_char buf[1024];
 
     if (!snxtitem(&np, EF_LAND, player->argp[1]))

src/lib/commands/new.c

@@ -46,8 +46,8 @@
 #include "optlist.h"
 #include "commands.h"
 
-
 #include <fcntl.h>
+#include <math.h>
 
 extern float start_education, start_happiness;
 extern float start_technology, start_research;
@@ -321,7 +321,6 @@ deity_build_land(int type, coord x, coord y, natid own, int tlev)
     struct lchrstr *lp;
     struct nstr_item nstr;
     struct natstr *natp;
-    double techfact(int, double);
     int lvec[I_MAX + 1];
     int extend = 1;
 

src/lib/commands/path.c

@@ -58,7 +58,7 @@ path(void)
     coord cx, cy;
     int i;
     int y;
-    s_char *pp, *p, *BestDistPath();
+    s_char *pp, *p;
     /* Note this is not re-entrant anyway, so we keep the buffers
        around */
     static s_char *mapbuf = (s_char *)0;

src/lib/commands/shut.c

@@ -38,8 +38,7 @@
 #include "nat.h"
 #include "file.h"
 #include "commands.h"
-
-extern void shutdown_sequence();
+#include "prototypes.h"
 
 int
 shut(void)

src/lib/commands/sinf.c

@@ -42,6 +42,7 @@
 #include "path.h"
 #include "file.h"
 #include "commands.h"
+#include "combat.h"
 
 int
 sinfra(void)
@@ -49,8 +50,6 @@ sinfra(void)
     struct sctstr sect;
     int nsect;
     struct nstr_sect nstr;
-    double sector_mcost();
-    double sector_strength(struct sctstr *);
 
     if (!snxtsct(&nstr, player->argp[1]))
 	return RET_SYN;

src/lib/commands/thre.c

@@ -49,7 +49,7 @@
 int
 thre(void)
 {
-    extern struct ichrstr *whatitem();
+    extern struct ichrstr *whatitem(s_char *, s_char *);
     struct sctstr sect;
     struct nstr_sect nstr;
     int val;

src/lib/commands/upgr.c

@@ -32,6 +32,8 @@
  *     Steve McClure, 1996-2000
  */
 
+#include <math.h>
+
 #include "misc.h"
 #include "player.h"
 #include "xy.h"