Building kernel module on Natty

[John D Lamb]

I get the following error trying to build a kernel module on Natty:

./include/linux/string.h:13:20: fatal error: stdarg.h: No such file or
directory

Here . is /lib/modules/2.6.38-11-generic-pae/build/ and string.h is
trying to #include stdarg.h, which can’t be found.

Am I missing some dependency — there is no stdarg.h in /lib/modules/… ?
There are copies of stdarg.h in the usual places. I write C/C++
programmes too often for these to be missing. But I want to be sure I
have the right version/dependencies for a kernel-module build.

-- 
JDL