It is a makefile command in dir "~/openwrt/scripts/config" (openwrt v12.09).

The whole scope is:

lkc_defs.h: $(src)/lkc_proto.h
    sed < $< > $@ 's/P(\([^,]*\),.*/#define \1 (\*\1_p)/'

But no lkc_defs.h generated after "make".
Its intention should be to interpret "lkc_proto.h" file to "lkc_defs.h"
like these:

in  "lkc_proto.h" file:
P(conf_read,int,(const char *name));

to be interpreted in "lkc_defs.h" file:
#define int conf_read(const char *name)

I don't know how to analyze "sed < $< > $@ 's/P(\([^,]*\),.*/#define \1 (\*\1_p)/'", could anyone help me?