INSTALL: add some notes how to create Linux headers directory
INSTALL: add some notes how to create Linux headers directory

wbx-github/uclibc-ng,kraj/uclibc-ng,kraj/uclibc-ng,wbx-github/uclibc-ng,wbx-github/uclibc-ng,wbx-github/uclibc-ng,kraj/uclibc-ng,kraj/uclibc-ng