lnav: fix HEAD readline linking.
lnav: fix HEAD readline linking.

Installing lnav from HEAD is currently broken. Currently the Formula
specifies 'readline' as a dependency. However, readline formula is
keg-only because 'OS X provides the BSD libedit library, which shadows
libreadline.'

With the latest changes in lnav build scripts, it detects and rejects
building with 'editline'. This change explicitly passes in the prefix to
readline during 'configure' stage to get around the problem.

Closes Homebrew/homebrew#38013.

Signed-off-by: Mike McQuaid <a17fed27eaa842282862ff7c1b9c8395a26ac320@mikemcquaid.com>

adam-moss/homebrew-core,smessmer/homebrew-core,robohack/homebrew-core,dsXLII/homebrew-core,bfontaine/homebrew-core,grhawk/homebrew-core,straxhaber/homebrew-core,sdorra/homebrew-core,sjackman/homebrew-core,uyjulian/homebrew-core,jdubois/homebrew-core,LinuxbrewTestBot/homebrew-core,edporras/homebrew-core,filcab/homebrew-core,moderndeveloperllc/homebrew-core,nbari/homebrew-core,FinalDes/homebrew-core,stgraber/homebrew-core,smessmer/homebrew-core,tkoenig/homebrew-core,nbari/homebrew-core,mbcoguno/homebrew-core,sdorra/homebrew-core,j-bennet/homebrew-core,adamliter/homebrew-core,BrewTestBot/homebrew-core,makigumo/homebrew-core,jabenninghoff/homebrew-core,ilovezfs/homebrew-core,phusion/homebrew-core,mvbattista/homebrew-core,aren55555/homebrew-core,maxim-belkin/homebrew-core,chrisfinazzo/homebrew-core,nandub/homebrew-core,spaam/homebrew-core,mfikes/homebrew-core,tkoenig/homebrew-core,mvitz/homebrew-core,Homebrew/homebrew-core,rwhogg/homebrew-core,FinalDes/homebrew-core,jdubois/homebrew-core,bfontaine/homebrew-core,kunickiaj/homebrew-core,mvitz/homebrew-core,cblecker/homebrew-core,jvehent/homebrew-core,sjackman/homebrew-core,ylluminarious/homebrew-core,robohack/homebrew-core,jdubois/homebrew-core,LinuxbrewTestBot/homebrew-core,chrisfinazzo/homebrew-core,reelsense/homebrew-core,zmwangx/homebrew-core,mvbattista/homebrew-core,grhawk/homebrew-core,ShivaHuang/homebrew-core,mahori/homebrew-core,andyjeffries/homebrew-core,lembacon/homebrew-core,dsXLII/homebrew-core,lembacon/homebrew-core,reelsense/homebrew-core,lemzwerg/homebrew-core,Moisan/homebrew-core,wolffaxn/homebrew-core,DomT4/homebrew-core,Linuxbrew/homebrew-core,rwhogg/homebrew-core,fvioz/homebrew-core,Moisan/homebrew-core,fvioz/homebrew-core,moderndeveloperllc/homebrew-core,aabdnn/homebrew-core,adam-moss/homebrew-core,JCount/homebrew-core,straxhaber/homebrew-core,mbcoguno/homebrew-core,zyedidia/homebrew-core,passerbyid/homebrew-core,jvillard/homebrew-core,jvillard/homebrew-core,battlemidget/homebrew-core,makigumo/homebrew-core,forevergenin/homebrew-core,DomT4/homebrew-core,jabenninghoff/homebrew-core,aabdnn/homebrew-core,ilovezfs/homebrew-core,battlemidget/homebrew-core,mbcoguno/homebrew-core,BrewTestBot/homebrew-core,gserra-olx/homebrew-core,bcg62/homebrew-core,passerbyid/homebrew-core,git-lfs/homebrew-core,uyjulian/homebrew-core,adamliter/homebrew-core,bcg62/homebrew-core,kuahyeow/homebrew-core,ylluminarious/homebrew-core,lembacon/homebrew-core,aren55555/homebrew-core,bigbes/homebrew-core,JCount/homebrew-core,kuahyeow/homebrew-core,jvillard/homebrew-core,zmwangx/homebrew-core,forevergenin/homebrew-core,mvitz/homebrew-core,lasote/homebrew-core,mahori/homebrew-core,lasote/homebrew-core,andyjeffries/homebrew-core,ShivaHuang/homebrew-core,edporras/homebrew-core,Homebrew/homebrew-core,Linuxbrew/homebrew-core,wolffaxn/homebrew-core,nandub/homebrew-core,j-bennet/homebrew-core,bcg62/homebrew-core,cblecker/homebrew-core,zyedidia/homebrew-core,filcab/homebrew-core,maxim-belkin/homebrew-core,mfikes/homebrew-core,spaam/homebrew-core,bigbes/homebrew-core,stgraber/homebrew-core,gserra-olx/homebrew-core,kunickiaj/homebrew-core,jvehent/homebrew-core,phusion/homebrew-core,wolffaxn/homebrew-core,lemzwerg/homebrew-core,git-lfs/homebrew-core