kbuild: always run 'make silentoldconfig' when tree is cleaned

If the file .kconfig.d is missing then make sure to run
'make silentoldconfig', since we have no way to detect if
a Kconfig file has been updated.

-kconfig.d is created by kconfig and is removed as part
of 'make clean' so the situation is likely to occur in reality.

Jan Beulich <JBeulich@novell.com> reported this bug.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

2 files changed, 7 insertions, 5 deletions

diff --git a/Makefile b/Makefile
index 922c7633797f..d3598ef3c777 100644
--- a/Makefile
+++ b/Makefile
@@ -477,18 +477,20 @@ ifeq ($(dot-config),1)
 
 # Read in dependencies to all Kconfig* files, make sure to run
 # oldconfig if changes are detected.
--include .config.cmd
+-include .kconfig.d
 
 include .config
 
 # If .config needs to be updated, it will be done via the dependency
 # that autoconf has on .config.
 # To avoid any implicit rule to kick in, define an empty command
-.config: ;
+.config .kconfig.d: ;
 
 # If .config is newer than include/linux/autoconf.h, someone tinkered
-# with it and forgot to run make oldconfig
-include/linux/autoconf.h: .config
+# with it and forgot to run make oldconfig.
+# If kconfig.d is missing then we are probarly in a cleaned tree so
+# we execute the config step to be sure to catch updated Kconfig files
+include/linux/autoconf.h: .kconfig.d .config
         $(Q)mkdir -p include/linux
         $(Q)$(MAKE) -f $(srctree)/Makefile silentoldconfig
 else
diff --git a/scripts/kconfig/util.c b/scripts/kconfig/util.c
index 1fa4c0b801b3..a711007ebe30 100644
--- a/scripts/kconfig/util.c
+++ b/scripts/kconfig/util.c
@@ -33,7 +33,7 @@ int file_write_dep(const char *name)
         FILE *out;
 
         if (!name)
-                name = ".config.cmd";
+                name = ".kconfig.d";
         out = fopen("..config.tmp", "w");
         if (!out)
                 return 1;