roken: move Heimdal vis.h extensions to separate header

vis.h is not built on platforms (such as macOS) that already have
that header, which resulted in prototypes for Heimdal-specific
vis.h extensions being absent.

Move those prototypes to a separate header, vis-extras.h, which
must be explicitly included in order to use the Heimdal extensions.

lib/asn1/extra.c

@@ -35,7 +35,8 @@
 
 #include "der_locl.h"
 #include "heim_asn1.h"
-#include "vis.h"
+#include <vis.h>
+#include <vis-extras.h>
 
 RCSID("$Id$");
 

lib/asn1/gen_template.c

@@ -41,6 +41,7 @@
 
 #include "gen_locl.h"
 #include <vis.h>
+#include <vis-extras.h>
 
 static const char *symbol_name(const char *, const Type *);
 static void generate_template_type(const char *, const char **, const char *, const char *, const char *,

lib/asn1/template.c

@@ -36,6 +36,7 @@
 #include "der_locl.h"
 #include <com_err.h>
 #include <vis.h>
+#include <vis-extras.h>
 
 struct asn1_type_func asn1_template_prim[A1T_NUM_ENTRY] = {
 #define el(name, type) {				\

lib/hx509/print.c

@@ -33,6 +33,7 @@
 
 #include "hx_locl.h"
 #include <vis.h>
+#include <vis-extras.h>
 
 /**
  * @page page_print Hx509 printing functions

lib/roken/Makefile.am

@@ -89,7 +89,7 @@ else
 vis_h = vis.h
 endif
 
-rkvis_SOURCES = vis.c $(vis_h)
+rkvis_SOURCES = vis.c $(vis_h) vis-extras.h
 rkvis_CPPFLAGS = -DTEST
 
 rkbase32_SOURCES = base32.c
@@ -179,6 +179,7 @@ libroken_la_SOURCES =		\
 	unvis.c			\
 	vis.c			\
 	$(vis_h)		\
+	vis-extras.h		\
 	warnerr.c		\
 	write_pid.c		\
 	xfree.c			\

lib/roken/NTMakefile

@@ -179,6 +179,7 @@ INCFILES = 			\
 	$(INCDIR)\stdbool.h	\
 	$(INCDIR)\syslog.h	\
 	$(INCDIR)\vis.h		\
+	$(INCDIR)\vis-extras.h	\
 !ifndef HAVE_STDINT_H
 	$(INCDIR)\stdint.h	\
 !endif

lib/roken/vis-extras.h

@@ -0,0 +1,27 @@
+#ifndef _VIS_EXTRAS_H_
+#define	_VIS_EXTRAS_H_
+
+#include <roken.h>
+
+ROKEN_CPP_START
+
+ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
+	rk_strasvis(char **, const char *, int, const char *);
+
+ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
+	rk_strasvisx(char **, const char *, size_t, int, const char *);
+
+ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
+	rk_strrasvis(char **, size_t *, const char *, int, const char *);
+
+ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
+	rk_strrasvisx(char **, size_t *, const char *, size_t, int, const char *);
+
+ROKEN_CPP_END
+
+#define strasvis(a, b, c, d)	    rk_strasvis(a, b, c, d)
+#define strasvisx(a, b, c, d)	    rk_strasvisx(a, b, c, d)
+#define strrasvis(a, b, c, d)	    rk_strrasvis(a, b, c, d)
+#define strrasvisx(a, b, c, d)	    rk_strrasvisx(a, b, c, d)
+
+#endif /* !_VIS_EXTRAS_H_ */

lib/roken/vis.c

@@ -396,6 +396,8 @@ rk_strsvisx(char *dst, const char *csrc, size_t len, int flag, const char *extra
  * buffer as needed.  Based on OpenBSD's stravis().
  */
 
+#include <vis-extras.h>
+
 ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
 rk_strasvis(char **out, const char *csrc, int flag, const char *extra)
 {

lib/roken/vis.hin

@@ -117,14 +117,6 @@ ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
 	rk_strvisx(char *, const char *, size_t, int);
 ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
 	rk_strsvisx(char *, const char *, size_t, int, const char *);
-ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
-	rk_strasvis(char **, const char *, int, const char *);
-ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
-	rk_strasvisx(char **, const char *, size_t, int, const char *);
-ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
-	rk_strrasvis(char **, size_t *, const char *, int, const char *);
-ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
-	rk_strrasvisx(char **, size_t *, const char *, size_t, int, const char *);
 ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
 	rk_strunvis(char *, const char *);
 ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL