kconfig: error out if a recursive variable references itself
When using a recursively expanded variable, it is a common mistake
to make circular reference.
For example, Make terminates the following code:
X = $(X)
Y := $(X)
Let's detect the circular expansion in Kconfig, too.
On the other hand, a function that recurses itself is a commonly-used
programming technique. So, Make does not check recursion in the
reference with 'call'. For example, the following code continues
running eternally:
X = $(call X)
Y := $(X)
Kconfig allows circular expansion if one or more arguments are given,
but terminates when the same function is recursively invoked 1000 times,
assuming it is a programming mistake.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
1 file changed