Fix include header file cannot be found

[jimwang118]

After completing the compilation, when I use the find_package(libtins CONFIG REQUIRED GLOBAL) or find_package(Pkgconfig REQUIRED) pkg_check_modules(tins REQUIRED IMPORTED_TARGET libtins) method to call the libtins library in my own project, I get the following prompt: fatal error: 'tins/tins.h' file not found.

By adding target_include_directories (tins PUBLIC $<INSTALL_INTERFACE:include>) in the cmakelists.txt file and deleting the redundant path tins in the cflags in the libtins.pc.in file, the header file #include <tins/tins.h> can be found in my test project .