Use dev-cpp/gflags for flag parsing

Packages describing “gflags” as local USE flag

Package “gflags” Flag Description
sci-libs/ceres-solver Use dev-cpp/gflags for flag parsing
dev-cpp/glog Use dev-cpp/gflags for flag parsing
media-libs/opencv Use Google's C++ argument parsing library

All packages providing a “gflags” USE flag (3)