Just the build dir is not going to work for srcdir!=builddir.
Requires: gstreamer-@GST_API_VERSION@
Version: @VERSION@
Libs: -L${libdir} -lgstinsertbin-@GST_API_VERSION@
-Cflags: -I${includedir}
+Cflags: -I@abs_top_srcdir@/gst-libs -I@abs_top_builddir@/gst-libs
Requires: gstreamer-@GST_API_VERSION@ gstreamer-video-@GST_API_VERSION@
Version: @VERSION@
Libs: -L${libdir} -lgstplayer-@GST_API_VERSION@
-Cflags: -I${includedir}
+Cflags: -I@abs_top_srcdir@/gst-libs -I@abs_top_builddir@/gst-libs
Requires: gstreamer-@GST_API_VERSION@ gstreamer-video-@GST_API_VERSION@
Version: @VERSION@
Libs: -L${libdir} -lgstwayland-@GST_API_VERSION@
-Cflags: -I${includedir}
+Cflags: -I@abs_top_srcdir@/gst-libs -I@abs_top_builddir@/gst-libs