gstreamer fails to compile without debuginfo

While working on reproducible builds for openSUSE, I found that our gstreamer-plugins-good package failed to build with

osc co openSUSE:Factory/gstreamer-plugins-good && cd $_
osc build --clean --noservice --disable-debuginfo standard

Because that omits the -g in CFLAGS.

cc  -o gst/isomp4/libgstisomp4.so gst/isomp4/libgstisomp4.so.p/isomp4-plugin.c.o gst/isomp4/libgstisomp4.so.p/gstrtpxqtdepay.c.o gst/isomp4/libgstisomp4.so.p/qtdemux.c.o gst/isomp4/libgstisomp4.so.p/qtdemux_types.c.o gst/isomp4/libgstisomp4.so.p/qtdemux_dump.c.o gst/isomp4/libgstisomp4.so.p/qtdemux_lang.c.o gst/isomp4/libgstisomp4.so.p/qtdemux_tags.c.o gst/isomp4/libgstisomp4.so.p/qtdemux_tree.c.o gst/isomp4/libgstisomp4.so.p/gstisoff.c.o gst/isomp4/libgstisomp4.so.p/gstqtmux.c.o gst/isomp4/libgstisomp4.so.p/gstqtmoovrecover.c.o gst/isomp4/libgstisomp4.so.p/atoms.c.o gst/isomp4/libgstisomp4.so.p/atomsrecovery.c.o gst/isomp4/libgstisomp4.so.p/descriptors.c.o gst/isomp4/libgstisomp4.so.p/properties.c.o gst/isomp4/libgstisomp4.so.p/gstqtmuxmap.c.o -Wl,--as-needed -Wl,--no-undefined -shared -fPIC -Wl,--start-group -Wl,-soname,libgstisomp4.so -Wl,-Bsymbolic-functions -flto=auto -O2 -Wall -D_FORTIFY_SOURCE=2 -fstack-protector-strong -funwind-tables -fasynchronous-unwind-tables -fstack-clash-protection -Werror=return-type -flto=auto /usr/lib64/libgstreamer-1.0.so /usr/lib64/libgobject-2.0.so /usr/lib64/libglib-2.0.so /usr/lib64/libgstriff-1.0.so /usr/lib64/libgstaudio-1.0.so /usr/lib64/libgstbase-1.0.so /usr/lib64/libgsttag-1.0.so /usr/lib64/libgstvideo-1.0.so /usr/lib64/libgstrtp-1.0.so /usr/lib64/libgstpbutils-1.0.so /usr/lib64/libz.so -Wl,--end-group
ninja: build stopped: subcommand failed.

Our build instructions look good to me.