cli: hush_modern: Enable if keyword

Adds support for "if then else" construct both for command line interface and
through run_command().

Signed-off-by: Francis Laniel <francis.laniel@amarulasolutions.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/common/cli_hush_modern.c b/common/cli_hush_modern.c
index 15bb1f0..6360747 100644
--- a/common/cli_hush_modern.c
+++ b/common/cli_hush_modern.c
@@ -33,6 +33,7 @@
  */
 #define ENABLE_HUSH_INTERACTIVE	1
 #define ENABLE_FEATURE_EDITING	1
+#define ENABLE_HUSH_IF		1
 /* No MMU in U-Boot */
 #define BB_MMU			0
 #define USE_FOR_NOMMU(...)	__VA_ARGS__
@@ -124,6 +125,11 @@
 	va_end(p);
 }
 
+static void bb_simple_error_msg(const char *s)
+{
+	bb_error_msg("%s", s);
+}
+
 static void *xmalloc(size_t size)
 {
 	void *p = NULL;
@@ -147,6 +153,11 @@
 	return p;
 }
 
+static void *xmemdup(const void *s, int n)
+{
+	return memcpy(xmalloc(n), s, n);
+}
+
 #define xstrdup		strdup
 #define xstrndup	strndup
 
diff --git a/common/cli_hush_upstream.c b/common/cli_hush_upstream.c
index a56ea6c..06af538 100644
--- a/common/cli_hush_upstream.c
+++ b/common/cli_hush_upstream.c
@@ -1487,7 +1487,6 @@
 	die_if_script();
 }
 
-#ifndef __U_BOOT__
 static void syntax_error(unsigned lineno UNUSED_PARAM, const char *msg)
 {
 	if (msg)
@@ -1496,7 +1495,6 @@
 		bb_simple_error_msg("syntax error");
 	die_if_script();
 }
-#endif /* !__U_BOOT__ */
 
 static void syntax_error_at(unsigned lineno UNUSED_PARAM, const char *msg)
 {
@@ -3961,7 +3959,6 @@
 		[PIPE_OR ] = "OR" ,
 		[PIPE_BG ] = "BG" ,
 	};
-#ifndef __U_BOOT__
 	static const char *RES[] = {
 		[RES_NONE ] = "NONE" ,
 # if ENABLE_HUSH_IF
@@ -3991,7 +3988,6 @@
 		[RES_XXXX ] = "XXXX" ,
 		[RES_SNTX ] = "SNTX" ,
 	};
-#endif /* !__U_BOOT__ */
 	static const char *const CMDTYPE[] = {
 		"{}",
 		"()",
@@ -4009,10 +4005,8 @@
 				lvl*2, "",
 				pin,
 				pi->num_cmds,
-#ifdef __U_BOOT__
 				(IF_HAS_KEYWORDS(pi->pi_inverted ? "! " :) ""),
 				RES[pi->res_word],
-#endif /* !__U_BOOT__ */
 				pi->followup, PIPE[pi->followup]
 		);
 		prn = 0;
@@ -9832,6 +9826,7 @@
 		rcode = 1; /* exitcode if redir failed */
 #ifndef __U_BOOT__
 		if (setup_redirects(command, &squirrel) == 0) {
+#endif /* !__U_BOOT__ */
 			debug_printf_exec(": run_list\n");
 //FIXME: we need to pass squirrel down into run_list()
 //for SH_STANDALONE case, or else this construct:
@@ -9840,10 +9835,11 @@
 //and in SH_STANDALONE mode, "find" is not execed,
 //therefore CLOEXEC on saved fd does not help.
 			rcode = run_list(command->group) & 0xff;
+#ifndef __U_BOOT__
 		}
 		restore_redirects(squirrel);
-		IF_HAS_KEYWORDS(if (pi->pi_inverted) rcode = !rcode;)
 #endif /* !__U_BOOT__ */
+		IF_HAS_KEYWORDS(if (pi->pi_inverted) rcode = !rcode;)
 		debug_leave();
 		debug_printf_exec("run_pipe: return %d\n", rcode);
 		return rcode;
@@ -10362,12 +10358,12 @@
 			break;
 		if (G_flag_return_in_progress == 1)
 			break;
+#endif /* !__U_BOOT__ */
 
 		IF_HAS_KEYWORDS(rword = pi->res_word;)
 		debug_printf_exec(": rword=%d cond_code=%d last_rword=%d\n",
 				rword, cond_code, last_rword);
 
-#endif /* !__U_BOOT__ */
 		sv_errexit_depth = G.errexit_depth;
 		if (
 #if ENABLE_HUSH_IF