ia32: Clearify if 32bit C/R is compile-disabled

Point that ia32 C/R was disabled due to missed packages.
Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>

Makefile.config

@@ -24,6 +24,9 @@ ifeq ($(SRCARCH),x86)
 ifeq ($(call try-cc,$(FEATURE_TEST_X86_COMPAT),-m32),true)
         export CONFIG_COMPAT := y
         FEATURE_DEFINES	+= -DCONFIG_COMPAT
+else
+        $(info Note: Building without ia32 C/R, missed packages:)
+        $(info $(info)      libc6-dev-i386, gcc-multilib)
 endif
 endif
 

criu/cr-check.c

@@ -1057,9 +1057,13 @@ static int check_loginuid(void)
 
 static int check_compat_cr(void)
 {
+#ifdef CONFIG_COMPAT
 	if (kdat_compat_sigreturn_test())
 		return 0;
 	pr_warn("compat_cr is not supported. Requires kernel >= v4.9\n");
+#else
+	pr_warn("CRIU built without CONFIG_COMPAT - can't C/R ia32\n");
+#endif
 	return -1;
 }