kconfig: save kernel version in .config file

Save kernel version info and date when writing .config file.
Tested with 'make {menuconfig|xconfig|gconfig}'.
Signed-off-by: Randy Dunlap <rddunlap@osdl.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

scripts/kconfig/confdata.c

@@ -8,6 +8,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <time.h>
 #include <unistd.h>
 
 #define LKC_DIRECT_LINK
@@ -268,6 +269,7 @@ int conf_write(const char *name)
 	char dirname[128], tmpname[128], newname[128];
 	int type, l;
 	const char *str;
+	time_t now;
 
 	dirname[0] = 0;
 	if (name && name[0]) {
@@ -301,14 +303,25 @@ int conf_write(const char *name)
 		if (!out_h)
 			return 1;
 	}
+	sym = sym_lookup("KERNELRELEASE", 0);
+	sym_calc_value(sym);
+	time(&now);
 	fprintf(out, "#\n"
 		     "# Automatically generated make config: don't edit\n"
-		     "#\n");
+		     "# Linux kernel version: %s\n"
+		     "# %s"
+		     "#\n",
+		     sym_get_string_value(sym),
+		     ctime(&now));
 	if (out_h)
 		fprintf(out_h, "/*\n"
 			       " * Automatically generated C config: don't edit\n"
+			       " * Linux kernel version: %s\n"
+			       " * %s"
 			       " */\n"
-			       "#define AUTOCONF_INCLUDED\n");
+			       "#define AUTOCONF_INCLUDED\n",
+			       sym_get_string_value(sym),
+			       ctime(&now));
 
 	if (!sym_change_count)
 		sym_clear_all_valid();