$ cat  /nix/store/10pzq1a8fkh8q4sysj8n6mv0w0nl0miq-opencv-3.4.1/lib/pkgconfig/opencv.pc
# Package Information for pkg-config

prefix=/nix/store/10pzq1a8fkh8q4sysj8n6mv0w0nl0miq-opencv-3.4.1
exec_prefix=${prefix}
libdir=${exec_prefix}//nix/store/10pzq1a8fkh8q4sysj8n6mv0w0nl0miq-opencv-3.4.1/lib
includedir_old=${prefix}/include/opencv
includedir_new=${prefix}/include

Name: OpenCV
Description: Open Source Computer Vision Library
Version: 3.4.1
Libs: -L${exec_prefix}//nix/store/10pzq1a8fkh8q4sysj8n6mv0w0nl0miq-opencv-3.4.1/lib -lopencv_stitching -lopencv_superres -lopencv_videostab -lopencv_aruco -lopencv_bgsegm -lopencv_bioinspired -lopencv_ccalib -lopencv_dnn_modern -lopencv_dnn_objdetect -lopencv_dpm -lopencv_face -lopencv_photo -lopencv_fuzzy -lopencv_hdf -lopencv_hfs -lopencv_img_hash -lopencv_line_descriptor -lopencv_optflow -lopencv_reg -lopencv_rgbd -lopencv_saliency -lopencv_sfm -lopencv_stereo -lopencv_structured_light -lopencv_phase_unwrapping -lopencv_surface_matching -lopencv_tracking -lopencv_datasets -lopencv_text -lopencv_dnn -lopencv_plot -lopencv_xfeatures2d -lopencv_shape -lopencv_video -lopencv_ml -lopencv_ximgproc -lopencv_calib3d -lopencv_features2d -lopencv_highgui -lopencv_videoio -lopencv_flann -lopencv_xobjdetect -lopencv_imgcodecs -lopencv_objdetect -lopencv_xphoto -lopencv_imgproc -lopencv_core
Libs.private: -ldl -lm -lpthread -lrt
Cflags: -I${includedir_old} -I${includedir_new}