Remove unsupported C99 style struct initializers in git-archive.

At least one older version of the Solaris C compiler doesn't support
the newer C99 style struct initializers.  To allow Git to compile
on those systems use an archive description struct which is easier
to initialize without the C99 struct initializer syntax.

Also since the archives array is not used by anyone other than
archive.c we can make it static.
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

archive.h

@@ -25,8 +25,6 @@ struct archiver {
 	parse_extra_args_fn_t parse_extra;
 };
 
-extern struct archiver archivers[];
-
 extern int parse_archive_args(int argc,
 			      const char **argv,
 			      struct archiver *ar);

builtin-archive.c

@@ -15,16 +15,14 @@
 static const char archive_usage[] = \
 "git-archive --format=<fmt> [--prefix=<prefix>/] [--verbose] [<extra>] <tree-ish> [path...]";
 
-struct archiver archivers[] = {
-	{
-		.name		= "tar",
-		.write_archive	= write_tar_archive,
-	},
-	{
-		.name		= "zip",
-		.write_archive	= write_zip_archive,
-		.parse_extra	= parse_extra_zip_args,
-	},
+static struct archiver_desc
+{
+	const char *name;
+	write_archive_fn_t write_archive;
+	parse_extra_args_fn_t parse_extra;
+} archivers[] = {
+	{ "tar", write_tar_archive, NULL },
+	{ "zip", write_zip_archive, parse_extra_zip_args },
 };
 
 static int run_remote_archiver(const char *remote, int argc,
@@ -88,7 +86,10 @@ static int init_archiver(const char *name, struct archiver *ar)
 
 	for (i = 0; i < ARRAY_SIZE(archivers); i++) {
 		if (!strcmp(name, archivers[i].name)) {
-			memcpy(ar, &archivers[i], sizeof(struct archiver));
+			memset(ar, 0, sizeof(*ar));
+			ar->name = archivers[i].name;
+			ar->write_archive = archivers[i].write_archive;
+			ar->parse_extra = archivers[i].parse_extra;
 			rv = 0;
 			break;
 		}