Any suggestions on why gimp-gap isn't building on OSX Leopard?

# port install gimp-gap ---> Fetching gimp-gap
---> Attempting to fetch gimp-gap-2.2.2.tar.bz2 from ftp://ftp.gimp.org/pub/gimp/plug-ins/v2.2/gap/ ---> Verifying checksum(s) for gimp-gap ---> Extracting gimp-gap
---> Configuring gimp-gap
---> Building gimp-gap with target all Error: Target org.macports.build returned: shell command " cd "/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_ports_graphics_gimp-gap/work/gimp-gap-2.2.2" && make all " returned error 2
Command output: /usr/bin/gcc-4.0 -O3 -g -Wall -Wno-switch -O2 -no-cpp-precomp -DHAVE_LRINTF -fno-common -pipe -fomit-frame-pointer -DHAVE_AV_CONFIG_H -I.. -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_GNU_SOURCE -c -o h263.o h263.c
In file included from h263.c:40:
mpeg4data.h:226: warning: pointer targets in initialization differ in signedness
mpeg4data.h:227: warning: pointer targets in initialization differ in signedness
mpeg4data.h:330: warning: pointer targets in initialization differ in signedness
mpeg4data.h:331: warning: pointer targets in initialization differ in signedness
h263.c: In function 'h263_pred_dc':
h263.c:1522: warning: pointer targets in assignment differ in signedness h263.c: In function 'mpeg4_encode_vol_header': h263.c:2374: warning: pointer targets in passing argument 2 of 'ff_write_quant_matrix' differ in signedness h263.c:2375: warning: pointer targets in passing argument 2 of 'ff_write_quant_matrix' differ in signedness h263.c: In function 'ff_mpeg4_pred_dc': h263.c:2503: warning: pointer targets in assignment differ in signedness /usr/bin/gcc-4.0 -O3 -g -Wall -Wno-switch -O2 -no-cpp-precomp -DHAVE_LRINTF -fno-common -pipe -fomit-frame-pointer -DHAVE_AV_CONFIG_H -I.. -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_GNU_SOURCE -c -o h261.o h261.c
/usr/bin/gcc-4.0 -O3 -g -Wall -Wno-switch -O2 -no-cpp-precomp -DHAVE_LRINTF -fno-common -pipe -fomit-frame-pointer -DHAVE_AV_CONFIG_H -I.. -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_GNU_SOURCE -c -o msmpeg4.o msmpeg4.c
msmpeg4.c: In function 'msmpeg4_pred_dc': msmpeg4.c:838: warning: pointer targets in assignment differ in signedness msmpeg4.c: In function 'msmpeg4_encode_block': msmpeg4.c:727: error: can't find a register in class 'BREG' while reloading 'asm'
{standard input}:14980:non-relocatable subtraction expression, "_msmpeg4v34_decode_mb" minus "L00000000003$pb" {standard input}:14980:symbol: "_msmpeg4v34_decode_mb" can't be undefined in a subtraction expression {standard input}:14957:non-relocatable subtraction expression, "_msmpeg4v12_decode_mb" minus "L00000000003$pb" {standard input}:14957:symbol: "_msmpeg4v12_decode_mb" can't be undefined in a subtraction expression {standard input}:14932:non-relocatable subtraction expression, "_wmv2_decode_mb" minus "L00000000003$pb" {standard input}:14932:symbol: "_wmv2_decode_mb" can't be undefined in a subtraction expression
make[4]: *** [msmpeg4.o] Error 1
make[3]: *** [lib] Error 2
make[2]: ***
[/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_ports_graphics_gimp-gap/work/gimp-gap-2.2.2/extern_libs/ffmpeg/libavformat/libavformat.a] Error 2
make[1]: *** [all-recursive] Error 1 make: *** [all] Error 2

Error: Status 1 encountered during processing.