I'd suggest to look at the freebsd ports build system. It is essentially declarative being built on top of Make language, and allows easy integration of variou

I'd suggest to look at the freebsd ports build system. It is essentially declarative being built on top of Make language, and allows easy integration of various open source components and dependencies. If targeting multiple platforms is of an essence, NetBSD pkgsrc provides a great model also built on top of Make.