[ruamoko] Create a va_copy for progs

In testing variable fw/precision in PR_Sprintf, I got a nasty reminder
of the limitations of the current progs ABI: passing @args to another QC
function does not work because the args list gets trampled but the
called function's locals. Thus, the need for a va_copy. It's not quite
the same as C's as it returns the destination args instead of copying
like memcpy, but it does copy the list from the source args to a
temporary buffer that is freed when the calling function returns.

include/rua_internal.h

@@ -49,6 +49,8 @@ void RUA_Obj_Init (struct progs_s *pr, int secure);
 
 void RUA_Plist_Init (struct progs_s *pr, int secure);
 
+void RUA_Runtime_Init (struct progs_s *pr, int secure);
+
 void RUA_Script_Init (progs_t *pr, int secure);
 
 void RUA_Set_Init (progs_t *pr, int secure);

libs/ruamoko/Makefile.am

@@ -18,4 +18,4 @@ libQFruamoko_la_SOURCES= \
 		pr_cmds.c \
 		rua_cbuf.c rua_cmd.c rua_cvar.c rua_hash.c rua_init.c \
 		rua_math.c rua_msgbuf.c rua_obj.c rua_plist.c rua_qfile.c rua_qfs.c \
-		rua_script.c rua_set.c rua_string.c
+		rua_runtime.c rua_script.c rua_set.c rua_string.c

libs/ruamoko/rua_init.c

@@ -45,6 +45,7 @@ static void (*init_funcs[])(progs_t *, int) = {
 	RUA_Plist_Init,
 	RUA_QFile_Init,
 	RUA_QFS_Init,
+	RUA_Runtime_Init,
 	RUA_Script_Init,
 	RUA_Set_Init,
 	RUA_String_Init,

libs/ruamoko/rua_runtime.c

@@ -0,0 +1,76 @@
+/*
+	bi_runtime.c
+
+	QuakeC runtime api
+
+	Copyright (C) 2020 Bill Currie
+
+	Author: Bill Currie <bill@taniwha.org>
+	Date: 2020/4/1
+
+	This program is free software; you can redistribute it and/or
+	modify it under the terms of the GNU General Public License
+	as published by the Free Software Foundation; either version 2
+	of the License, or (at your option) any later version.
+
+	This program is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+
+	See the GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with this program; if not, write to:
+
+		Free Software Foundation, Inc.
+		59 Temple Place - Suite 330
+		Boston, MA  02111-1307, USA
+
+*/
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#ifdef HAVE_STRING_H
+# include <string.h>
+#endif
+#ifdef HAVE_STRINGS_H
+# include <strings.h>
+#endif
+#include <stdlib.h>
+
+#include "qfalloca.h"
+
+#if defined(_WIN32) && defined(HAVE_MALLOC_H)
+#include <malloc.h>
+#endif
+
+#include "QF/progs.h"
+
+#include "rua_internal.h"
+
+static void
+bi_va_copy (progs_t *pr)
+{
+	__auto_type src_args = (pr_va_list_t *) &P_POINTER (pr, 0);
+	__auto_type src_list = &G_STRUCT (pr, pr_type_t, src_args->list);
+	size_t      parm_size = pr->pr_param_size * sizeof(pr_type_t);
+	size_t      size = src_args->count * parm_size;
+	string_t    dst_list_block = PR_AllocTempBlock (pr, size);
+	__auto_type dst_list = (pr_type_t *) PR_GetString (pr, dst_list_block);
+
+	memcpy (dst_list, src_list, size);
+	R_PACKED (pr, pr_va_list_t).count = src_args->count;
+	R_PACKED (pr, pr_va_list_t).list = PR_SetPointer (pr, dst_list);
+}
+
+static builtin_t builtins[] = {
+	{"va_copy",		bi_va_copy,		-1},
+	{0}
+};
+
+void
+RUA_Runtime_Init (progs_t *pr, int secure)
+{
+	PR_RegisterBuiltins (pr, builtins);
+}

ruamoko/include/runtime.h

@@ -100,6 +100,10 @@ typedef enum {
 
 @extern void *PR_FindGlobal (string name);	//FIXME where?
 
+// copies the list in src to a temporary buffer that will be freed when the
+// calling function returns, and places the pointer to the buffer into the
+// returned va_list. The count is copies as-is.
+@extern @va_list va_copy(@va_list src);
 #endif	//__ruamoko_runtime_h_
 /**
 	\}

ruamoko/lib/Makefile.am

@@ -36,7 +36,7 @@ r_depfiles_remade=
 
 libr_a_SOURCES=\
 	cbuf.r cmd.r cvar.r hash.r msgbuf.r plist.r qfile.r qfs.r script.r \
-	sound.r string.r math.r types.r \
+	sound.r string.r math.r types.r va_list.r \
 	obj_forward.r \
 	Object.r Protocol.r \
 	AutoreleasePool.r Array.r Array+Private.r Entity.r PropertyList.r Set.r

ruamoko/lib/va_list.r

@@ -0,0 +1,3 @@
+#include <runtime.h>
+
+@va_list va_copy(@va_list src) = #0;

ruamoko/qwaq/ui/view.r

@@ -239,7 +239,7 @@ updateScreenCursor (View *view)
 {
 	pos.x += xpos;
 	pos.y += ypos;
-	[textContext mvvprintf: pos, fmt, @args];
+	[textContext mvvprintf: pos, fmt, va_copy (@args)];
 }
 
 - (void) mvvprintf: (Point) pos, string fmt, @va_list args