Add pkg-config file

Build/pkgconfig/bento4.pc.in

@@ -0,0 +1,9 @@
+prefix=@CMAKE_INSTALL_PREFIX@
+includedir=${prefix}/@CMAKE_INSTALL_INCLUDEDIR@
+libdir=${prefix}/@CMAKE_INSTALL_LIBDIR@
+
+Name: @PROJECT_NAME@
+Description: Full-featured MP4 format, MPEG DASH, HLS, CMAF SDK and tools
+Version: @BENTO4_VERSION@
+Libs: -L${libdir} -lap4
+Cflags: -I${includedir}/bento4

CMakeLists.txt

@@ -124,6 +124,12 @@ configure_package_config_file(
     INSTALL_DESTINATION "${config_install_dir}"
 )
 
+configure_file(
+    "Build/pkgconfig/bento4.pc.in"
+    "${generated_dir}/bento4.pc"
+    @ONLY
+)
+
 install(
     TARGETS ap4 ${BENTO4_APPS_LOWERCASE}
     EXPORT "${TARGETS_EXPORT_NAME}"
@@ -143,6 +149,11 @@ install(
     DESTINATION "${config_install_dir}"
 )
 
+install(
+    FILES "${generated_dir}/bento4.pc"
+    DESTINATION "${CMAKE_INSTALL_LIBDIR}/pkgconfig"
+)
+
 install(
     EXPORT "${TARGETS_EXPORT_NAME}"
     NAMESPACE "${namespace}"