Fix idmap2 compiling against musl

Add missing includes that are not transitively provided when compiling
against musl.

Bug: 190084016
Test: m USE_HOST_MUSL=true
Change-Id: If8829cebb0c62b539d7a336b75cf106755588cdd
Merged-In: If8829cebb0c62b539d7a336b75cf106755588cdd
1 file changed