Modern software projects rely on build systems and build scripts to build executable artifacts correctly and efficiently. However, developing build scripts is error-prone. Dependency-related errors in build scripts, mainly including missing dependencies and redundant dependencies, are common in various kinds of software projects. These errors could lead to build failures, incorrect build results or poor performance in an incremental or/and parallel build. To detect such errors, various detection techniques are proposed based on different kinds of dependencies graphs. However, these techniques suffer from either low efficiency or high false positive problems, due to the deficiency of the underlying dependency graphs. In this work, we design a new dependency graph, the unified dependency graph (UDG), which leverages both static and dynamic information to uniformly encode the declared and actual dependencies between build targets and files. The construction of UDG facilitates the efficient and precise detection of detect dependency errors via simple graph traversals. We implement the proposed approach as a tool, Veribuild, and evaluate it on 42 well-maintained open-source projects. The experimental results have demonstrated that Veribuild has a good performance in efficiency and precision. Without losing precision, Veribuild incurs 58.2X less overhead than the state-of-the-art approach. By the time of writing, 398 detected dependency issues have been confirmed by the developers.