Build-in "git-shell"

This trivially makes "git-shell" a built-in.  It makes the executable even
fatter, though.

And MinGW removed git-shell only because of the funny dependencies; there
is no reason to do so anymore.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Tested-on-MinGW-by: Johannes Sixt <johannes.sixt@telecom.at>

Makefile

@@ -546,6 +546,7 @@ BUILTIN_OBJS += builtin-rev-parse.o
 BUILTIN_OBJS += builtin-revert.o
 BUILTIN_OBJS += builtin-rm.o
 BUILTIN_OBJS += builtin-send-pack.o
+BUILTIN_OBJS += builtin-shell.o
 BUILTIN_OBJS += builtin-shortlog.o
 BUILTIN_OBJS += builtin-show-branch.o
 BUILTIN_OBJS += builtin-show-ref.o
@@ -821,7 +822,6 @@ EXTLIBS += -lz
 ifndef NO_POSIX_ONLY_PROGRAMS
 	PROGRAMS += git-daemon$X
 	PROGRAMS += git-imap-send$X
-	PROGRAMS += git-shell$X
 endif
 ifndef NO_OPENSSL
 	OPENSSL_LIBSSL = -lssl

builtin-shell.c

@@ -2,6 +2,7 @@
 #include "quote.h"
 #include "exec_cmd.h"
 #include "strbuf.h"
+#include "builtin.h"
 
 static int do_generic_cmd(const char *me, char *arg)
 {
@@ -44,7 +45,7 @@ static struct commands {
 	{ NULL },
 };
 
-int main(int argc, char **argv)
+int cmd_shell(int argc, const char **argv, const char *prefix)
 {
 	char *prog;
 	struct commands *cmd;
@@ -62,7 +63,7 @@ int main(int argc, char **argv)
 	else if (argc != 3 || strcmp(argv[1], "-c"))
 		die("What do you think I am? A shell?");
 
-	prog = argv[2];
+	prog = xstrdup(argv[2]);
 	if (!strncmp(prog, "git", 3) && isspace(prog[3]))
 		/* Accept "git foo" as if the caller said "git-foo". */
 		prog[3] = '-';

builtin.h

@@ -88,6 +88,7 @@ extern int cmd_rev_parse(int argc, const char **argv, const char *prefix);
 extern int cmd_revert(int argc, const char **argv, const char *prefix);
 extern int cmd_rm(int argc, const char **argv, const char *prefix);
 extern int cmd_send_pack(int argc, const char **argv, const char *prefix);
+extern int cmd_shell(int argc, const char **argv, const char *prefix);
 extern int cmd_shortlog(int argc, const char **argv, const char *prefix);
 extern int cmd_show(int argc, const char **argv, const char *prefix);
 extern int cmd_show_branch(int argc, const char **argv, const char *prefix);

git.c

@@ -338,6 +338,7 @@ static void handle_internal_command(int argc, const char **argv)
 		{ "revert", cmd_revert, RUN_SETUP | NEED_WORK_TREE },
 		{ "rm", cmd_rm, RUN_SETUP },
 		{ "send-pack", cmd_send_pack, RUN_SETUP },
+		{ "shell", cmd_shell },
 		{ "shortlog", cmd_shortlog, USE_PAGER },
 		{ "show-branch", cmd_show_branch, RUN_SETUP },
 		{ "show", cmd_show, RUN_SETUP | USE_PAGER },