building with jhbuild, -Werror is turned on by default. The following occurs:

 gcc -DHAVE_CONFIG_H -I. -I. -I../.. -I../../gst-libs -I../../gst-libs -pthread
-D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64
-I/home/nathanr/bin/gnome2-cvs/include/glib-2.0
-I/home/nathanr/bin/gnome2-cvs/lib64/glib-2.0/include
-I/home/nathanr/bin/gnome2-cvs/include/libxml2
-I/home/nathanr/bin/gnome2-cvs/include/gstreamer-0.8 -DGST_DISABLE_DEPRECATED
-Wall -Werror -g -O2 -MT libgstadder_la-gstadder.lo -MD -MP -MF
.deps/libgstadder_la-gstadder.Tpo -c gstadder.c  -fPIC -DPIC -o
.libs/libgstadder_la-gstadder.o
gstadder.c: In function `gst_adder_loop':
gstadder.c:409: warning: comparison is always false due to limited range of data
type
gstadder.c:409: warning: comparison is always false due to limited range of data
type
make[3]: *** [libgstadder_la-gstadder.lo] Error 1
make[3]: Leaving directory `/home/nathanr/download/gnome-cvs/gst-plugins/gst/adder'
make[2]: *** [all-recursive] Error 1
make[2]: Leaving directory `/home/nathanr/download/gnome-cvs/gst-plugins/gst'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/home/nathanr/download/gnome-cvs/gst-plugins'
make: *** [all] Error 2
*** error during stage build of gst-plugins: could not build module *** [70/91]

Offending line:
out[i] = CLAMP (out[i] + in[i], MIN_INT_32, MAX_INT_32);

The preprocessor output ("gcc -E") for that line is:

out[i] = (((out[i] + in[i]) > (2147483647L)) ? (2147483647L) : (((out[i] +
in[i]) < ((-2147483647L -1L))) ? ((-2147483647L -1L)) : (out[i] + in[i])));

It turns out the compiler is smart enough to work out that they are the bounds
of an gint32, and hence the condition is always false. The patch simply casts
the comparison to a gint64. Here's the patch to fix this:

--- gstadder.c.~1.55.~  2004-07-09 20:56:49.000000000 +1000
+++ gstadder.c  2004-08-30 22:14:54.322727752 +1000
@@ -406,7 +406,7 @@
           gint32 *out = (gint32 *) GST_BUFFER_DATA (buf_out);
  
           for (i = 0; i < GST_BUFFER_SIZE (buf_out) / 4; i++)
-            out[i] = CLAMP (out[i] + in[i], MIN_INT_32, MAX_INT_32);
+            out[i] = CLAMP (((gint64) out[i]) + ((gint64)in[i]), MIN_INT_32,
MAX_INT_32);
         } else if (adder->width == 16) {
           gint16 *in = (gint16 *) raw_in;
           gint16 *out = (gint16 *) GST_BUFFER_DATA (buf_out);