kbuild: modpost build fix

scripts/mod/modpost.c: In function `check_license':
scripts/mod/modpost.c:1094: parse error before `const'
scripts/mod/modpost.c:1095: `basename' undeclared (first use in this function)
scripts/mod/modpost.c:1095: (Each undeclared identifier is reported only once
scripts/mod/modpost.c:1095: for each function it appears in.)

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>