Add generation of pkgconfig file

libxisf.pc.in

@@ -0,0 +1,13 @@
+prefix="@CMAKE_INSTALL_PREFIX@"
+exec_prefix="${prefix}"
+libdir="${exec_prefix}/@CMAKE_INSTALL_LIBDIR@"
+includedir="${prefix}/@CMAKE_INSTALL_INCLUDEDIR@"
+
+Name: @PROJECT_NAME@
+Description: @CMAKE_PROJECT_DESCRIPTION@
+URL: @CMAKE_PROJECT_HOMEPAGE_URL@
+Version: @PROJECT_VERSION@
+Requires.private: @PC_LIBS_REQUIRE@
+Cflags: -I"${includedir}"
+Libs: -L"${libdir}" -lXISF
+Libs.private: -L"${libdir}" @PC_LIBS_REQUIRE@