kconfig: autogenerated config_is_xxx macro

this will allow to use to use

	if(config_is_xxx())
	if(config_is_xxx_module())

in the code instead of

	#ifdef CONFIG_xxx
	#ifdef CONFIG_xxx_MODULE

and now let the compiler remove the non usefull code and not the
pre-processor

as done in the mach-types for arm as exmaple
Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>

scripts/kconfig/confdata.c

@@ -778,6 +778,29 @@ static int conf_split_config(void)
 	return res;
 }
 
+static void conf_write_function_autoconf(FILE *out, char* conf, char* name,
+					 int val)
+{
+	char c;
+	char *tmp, *d;
+
+	d = strdup(conf);
+	tmp = d;
+	while ((c = *conf++))
+		*d++ = tolower(c);
+
+	fprintf(out, "#define %sis_", tmp);
+	free(tmp);
+
+	d = strdup(name);
+	tmp = d;
+	while ((c = *name++))
+		*d++ = tolower(c);
+	fprintf(out, "%s%s() %d\n", tmp, (val > 1) ? "_module" : "",
+		      val ? 1 : 0);
+	free(tmp);
+}
+
 int conf_write_autoconf(void)
 {
 	struct symbol *sym;
@@ -785,6 +808,7 @@ int conf_write_autoconf(void)
 	const char *name;
 	FILE *out, *tristate, *out_h;
 	int i;
+	int fct_val;
 
 	sym_clear_all_valid();
 
@@ -825,6 +849,7 @@ int conf_write_autoconf(void)
 		       rootmenu.prompt->text);
 
 	for_all_symbols(i, sym) {
+		fct_val = 1;
 		sym_calc_value(sym);
 		if (!(sym->flags & SYMBOL_WRITE) || !sym->name)
 			continue;
@@ -838,12 +863,14 @@ int conf_write_autoconf(void)
 		case S_TRISTATE:
 			switch (sym_get_tristate_value(sym)) {
 			case no:
+				fct_val = 0;
 				break;
 			case mod:
 				fprintf(tristate, "%s%s=M\n",
 				    CONFIG_, sym->name);
 				fprintf(out_h, "#define %s%s_MODULE 1\n",
 				    CONFIG_, sym->name);
+				fct_val = 2;
 				break;
 			case yes:
 				if (sym->type == S_TRISTATE)
@@ -870,8 +897,10 @@ int conf_write_autoconf(void)
 			    CONFIG_, sym->name, str);
 			break;
 		default:
+			fct_val = 0;
 			break;
 		}
+		conf_write_function_autoconf(out_h, CONFIG_, sym->name, fct_val);
 	}
 	fclose(out);
 	fclose(tristate);