[PATCH for-5.1] Makefile: Remove config-devices.mak on "make clean"

[Peter Maydell]

The config-devices.mak files are generated by "make", and so they
should be deleted by "make clean".

(This is different from config-host.mak and config-all-disas.mak,
which are created by "configure" and so only deleted by
"make distclen".)

If we don't delete these files on "make clean", then the build
tree is left in a state where it has the config-devices.mak
file but not the config-devices.mak.d file, and make will not
realize that it needs to rebuild config-devices.mak if, for
instance, hw/sd/Kconfig changes.

NB: config-all-devices.mak is also generated by "make", but we
already remove it on "make clean".

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
I didn't remove the existing 'rm -f $(SUBDIR_DEVICES_MAK)'
from the 'distclean' rules on the basis that config-all-devices.mak
is explicitly removed in both 'distclean' and 'clean', despite
'distclean' depending on 'clean'...
---
 Makefile | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Makefile b/Makefile
index 32345c610ee..c2120d8d48d 100644
--- a/Makefile
+++ b/Makefile
@@ -775,6 +775,7 @@ clean: recurse-clean
        rm -f storage-daemon/qapi/qapi-gen-timestamp
        rm -rf qga/qapi-generated
        rm -f config-all-devices.mak
+       rm -f $(SUBDIR_DEVICES_MAK)
 
 VERSION ?= $(shell cat VERSION)
 
-- 
2.20.1