rc: only have single instance of a symbol, extern in header (thanks mcf)

sys/src/cmd/rc/code.c

@@ -7,7 +7,7 @@
 #define	c1	t->child[1]
 #define	c2	t->child[2]
 code *codebuf;
-int codep, ncode, codeline;
+static int codep, ncode, codeline;
 #define	emitf(x) ((codep!=ncode || morecode()), codebuf[codep].f = (x), codep++)
 #define	emiti(x) ((codep!=ncode || morecode()), codebuf[codep].i = (x), codep++)
 #define	emits(x) ((codep!=ncode || morecode()), codebuf[codep].s = (x), codep++)

sys/src/cmd/rc/exec.c

@@ -4,6 +4,11 @@
 #include "io.h"
 #include "fns.h"
 
+char *argv0="rc";
+io *err;
+int mypid;
+thread *runq;
+
 /*
  * Start executing the given code at the given pc with the given redirection
  */
@@ -216,8 +221,6 @@ shuffleredir(void)
  * fabricate bootstrap code and start it (*=(argv);. -bq /usr/lib/rcmain $*)
  * start interpreting code
  */
-char *argv0="rc";
-
 void
 main(int argc, char *argv[])
 {

sys/src/cmd/rc/exec.h

@@ -57,16 +57,17 @@ struct thread{
 	char *status;			/* status for Xpipewait */
 	thread *ret;			/* who continues when this finishes */
 };
-
-thread *runq;
+extern thread *runq;
 void turfstack(var*);
 
+extern int mypid;
+extern int ntrap;			/* number of outstanding traps */
+extern int trap[NSIG];			/* number of outstanding traps per type */
+
 code *codecopy(code*);
-code *codebuf;				/* compiler output */
+extern code *codebuf;			/* compiler output */
 extern int ifnot;
 
-int ntrap;				/* number of outstanding traps */
-int trap[NSIG];				/* number of outstanding traps per type */
 struct builtin{
 	char *name;
 	void (*fnc)(void);
@@ -82,5 +83,3 @@ void startfunc(var*, word*, var*, redir*);
 
 char *srcfile(thread*);
 char *getstatus(void);
-
-extern char *argv0;

sys/src/cmd/rc/io.h

@@ -5,7 +5,6 @@ struct io{
 	unsigned char *buf, *bufp, *ebuf;
 	io	*next;
 };
-io *err;
 
 io *openiofd(int), *openiostr(void), *openiocore(void*, int);
 void pchr(io*, int);

sys/src/cmd/rc/rc.h

@@ -123,8 +123,7 @@ var *vlook(char*), *gvlook(char*), *newvar(char*, var*);
 void setvar(char*, word*), freevar(var*);
 
 #define	NVAR	521
-
-var *gvar[NVAR];				/* hash for globals */
+extern var *gvar[NVAR];		/* hash for globals */
 
 #define	new(type)	((type *)emalloc(sizeof(type)))
 
@@ -132,8 +131,6 @@ void *emalloc(long);
 void *erealloc(void *, long);
 char *estrdup(char*);
 
-int mypid;
-
 /*
  * Glob character escape in strings:
  *	In a string, GLOB must be followed by *?[ or GLOB.
@@ -152,10 +149,10 @@ int mypid;
 #define fourbyte(c)	(((c)&0xf8)==0xf0)
 #define xbyte(c)	(((c)&0xc0)==0x80)
 
-extern char **argp;
-extern char **args;
+extern char *argv0;
 extern int nerror;		/* number of errors encountered during compilation */
 extern int doprompt;		/* is it time for a prompt? */
+extern io *err;
 
 /*
  * Which fds are the reading/writing end of a pipe?
@@ -166,3 +163,4 @@ extern int doprompt;		/* is it time for a prompt? */
 #define	PRD	0
 #define	PWR	1
 extern char Rcmain[], Fdprefix[];
+extern char *Signame[];

sys/src/cmd/rc/subr.c

@@ -1,5 +1,4 @@
 #include "rc.h"
-#include "exec.h"
 #include "io.h"
 #include "fns.h"
 

sys/src/cmd/rc/trap.c

@@ -2,7 +2,9 @@
 #include "exec.h"
 #include "fns.h"
 #include "io.h"
-extern char *Signame[];
+
+int ntrap;
+int trap[NSIG];
 
 void
 dotrap(void)

sys/src/cmd/rc/var.c

@@ -2,6 +2,8 @@
 #include "exec.h"
 #include "fns.h"
 
+var *gvar[NVAR];
+
 int
 hash(char *s, int n)
 {