kconfig: fix oldconfig to generate .config.cmd

Since the recent update of Kconfig to the Kconfig infrastructure found
in 2.6.30 kernels, make oldconfig was broken because it didn't
generate the .config.cmd file. This is done by a call to the
conf_write_autoconf() function.

Moreover, this process was also broken because the
conf_get_autoconfig_name() function was reading the environment
variable BUILDROOT_AUTOCONF while the main Makefile is passing it as
KCONFIG_AUTOCONFIG. We also remove the fallback on
"$(BR2_DEPENDS_DIR)/config/auto.conf" since we are not able to expand
BR2_DEPENDS_DIR at this point. Therefore, the KCONFIG_AUTOCONFIG
envionment variable *must* be set.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/config/conf.c

@@ -611,6 +611,10 @@ int main(int ac, char **av)
 			fprintf(stderr, _("\n*** Error during writing of the Buildroot configuration.\n\n"));
 			exit(1);
 		}
+		if (conf_write_autoconf()) {
+			fprintf(stderr, _("\n*** Error during update of the Buildroot configuration.\n\n"));
+			return 1;
+		}
 	}
 	return 0;
 }

package/config/confdata.c

@@ -44,9 +44,7 @@ const char *conf_get_configname(void)
 
 const char *conf_get_autoconfig_name(void)
 {
-	char *name = getenv("BUILDROOT_AUTOCONFIG");
+	return getenv("KCONFIG_AUTOCONFIG");
-
-	return name ? name : "$(BR2_DEPENDS_DIR)/config/auto.conf";
 }
 
 static char *conf_expand_value(const char *in)

package/config/kconfig-to-buildroot2.patch

@@ -1,7 +1,7 @@
 ---
  Makefile            |    7 +++
  README.buildroot2   |   22 ++++++++++
- conf.c              |   13 ++----
+ conf.c              |   17 ++++----
  confdata.c          |  101 ++++++++++++++++++++++++++------------------------
  expr.c              |   42 ++++++++++----------
  gconf.c             |    4 -
@@ -11,7 +11,7 @@
  util.c              |  105 +++++++++++++++++++++++++++++++++++++++++++++++++++-
  zconf.tab.c_shipped |    2 
  zconf.y             |    2 
- 12 files changed, 241 insertions(+), 103 deletions(-)
+ 12 files changed, 244 insertions(+), 104 deletions(-)
 
 Index: config/Makefile
 ===================================================================
@@ -91,7 +91,7 @@ Index: config/conf.c
  				return 1;
  			}
  		}
-@@ -600,16 +599,16 @@
+@@ -600,18 +599,22 @@
  		 * All other commands are only used to generate a config.
  		 */
  		if (conf_get_changed() && conf_write(NULL)) {
@@ -110,7 +110,13 @@ Index: config/conf.c
 +			fprintf(stderr, _("\n*** Error during writing of the Buildroot configuration.\n\n"));
  			exit(1);
  		}
++		if (conf_write_autoconf()) {
++			fprintf(stderr, _("\n*** Error during update of the Buildroot configuration.\n\n"));
++			return 1;
++		}
  	}
+ 	return 0;
+ }
 Index: config/confdata.c
 ===================================================================
 --- config.orig/confdata.c
@@ -132,7 +138,7 @@ Index: config/confdata.c
  
  static void conf_warning(const char *fmt, ...)
  {
-@@ -36,16 +37,16 @@
+@@ -36,16 +37,14 @@
  
  const char *conf_get_configname(void)
  {
@@ -145,14 +151,13 @@ Index: config/confdata.c
  const char *conf_get_autoconfig_name(void)
  {
 -	char *name = getenv("KCONFIG_AUTOCONFIG");
-+	char *name = getenv("BUILDROOT_AUTOCONFIG");
+-
- 
 -	return name ? name : "include/config/auto.conf";
-+	return name ? name : "$(BR2_DEPENDS_DIR)/config/auto.conf";
++	return getenv("KCONFIG_AUTOCONFIG");
  }
  
  static char *conf_expand_value(const char *in)
-@@ -219,22 +220,22 @@
+@@ -219,22 +218,22 @@
  		sym = NULL;
  		switch (line[0]) {
  		case '#':
@@ -179,7 +184,7 @@ Index: config/confdata.c
  				if (sym->type == S_UNKNOWN)
  					sym->type = S_BOOLEAN;
  			}
-@@ -251,12 +252,8 @@
+@@ -251,12 +250,8 @@
  				;
  			}
  			break;
@@ -194,7 +199,7 @@ Index: config/confdata.c
  			if (!p)
  				continue;
  			*p++ = 0;
-@@ -267,13 +264,13 @@
+@@ -267,13 +262,13 @@
  					*p2 = 0;
  			}
  			if (def == S_DEF_USER) {
@@ -210,7 +215,7 @@ Index: config/confdata.c
  				if (sym->type == S_UNKNOWN)
  					sym->type = S_OTHER;
  			}
-@@ -443,7 +440,7 @@
+@@ -443,7 +438,7 @@
  	if (!out)
  		return 1;
  
@@ -219,7 +224,7 @@ Index: config/confdata.c
  	sym_calc_value(sym);
  	time(&now);
  	env = getenv("KCONFIG_NOTIMESTAMP");
-@@ -452,10 +449,8 @@
+@@ -452,10 +447,8 @@
  
  	fprintf(out, _("#\n"
  		       "# Automatically generated make config: don't edit\n"
@@ -230,7 +235,7 @@ Index: config/confdata.c
  		     use_timestamp ? "# " : "",
  		     use_timestamp ? ctime(&now) : "");
  
-@@ -489,19 +484,19 @@
+@@ -489,19 +482,19 @@
  			case S_TRISTATE:
  				switch (sym_get_tristate_value(sym)) {
  				case no:
@@ -254,7 +259,7 @@ Index: config/confdata.c
  				while (1) {
  					l = strcspn(str, "\"\\");
  					if (l) {
-@@ -517,12 +512,12 @@
+@@ -517,12 +510,12 @@
  			case S_HEX:
  				str = sym_get_string_value(sym);
  				if (str[0] != '0' || (str[1] != 'x' && str[1] != 'X')) {
@@ -269,7 +274,7 @@ Index: config/confdata.c
  				break;
  			}
  		}
-@@ -564,6 +559,7 @@
+@@ -564,6 +557,7 @@
  {
  	const char *name;
  	char path[128];
@@ -277,7 +282,7 @@ Index: config/confdata.c
  	char *s, *d, c;
  	struct symbol *sym;
  	struct stat sb;
-@@ -572,8 +568,20 @@
+@@ -572,8 +566,20 @@
  	name = conf_get_autoconfig_name();
  	conf_read_simple(name, S_DEF_AUTO);
  
@@ -299,7 +304,7 @@ Index: config/confdata.c
  
  	res = 0;
  	for_all_symbols(i, sym) {
-@@ -666,9 +674,11 @@
+@@ -666,9 +672,11 @@
  		close(fd);
  	}
  out:
@@ -314,7 +319,7 @@ Index: config/confdata.c
  	return res;
  }
  
-@@ -683,7 +693,7 @@
+@@ -683,7 +691,7 @@
  
  	sym_clear_all_valid();
  
@@ -323,7 +328,7 @@ Index: config/confdata.c
  
  	if (conf_split_config())
  		return 1;
-@@ -698,22 +708,19 @@
+@@ -698,22 +706,19 @@
  		return 1;
  	}
  
@@ -350,7 +355,7 @@ Index: config/confdata.c
  
  	for_all_symbols(i, sym) {
  		sym_calc_value(sym);
-@@ -726,19 +733,19 @@
+@@ -726,19 +731,19 @@
  			case no:
  				break;
  			case mod:
@@ -376,7 +381,7 @@ Index: config/confdata.c
  			while (1) {
  				l = strcspn(str, "\"\\");
  				if (l) {
-@@ -758,14 +765,14 @@
+@@ -758,14 +763,14 @@
  		case S_HEX:
  			str = sym_get_string_value(sym);
  			if (str[0] != '0' || (str[1] != 'x' && str[1] != 'X')) {