Fix 76 build cleanups

[claud9999]

Closes #76

This simplifies the build scripts and improves them:

• relying on setCompilePath.sh for most env vars
• using $INSTALLDIR rather than $INSTALL (which confuses GNU libtool.)
• using set -e in all scripts to have them fail if any step fails

I am sure there's more improvements that can be made (I am guessing there's still some static linking that is unnecessary, would be good to add "strip" to most everything [maybe have a top-level config whether to build "debug" or "release" versions], relying more on tool-provided make install installation, etc.)

[claud9999]

going to re-do the PR to resolve conflict