$ LC_ALL=C makepkg -fs
==> Making package: lib32-rtmpdump 2.4-1 (Tue Jan 24 19:24:45 BRST 2012)
==> Checking runtime dependencies...
==> Checking buildtime dependencies...
==> Retrieving Sources...
  -> Found rtmpdump-2.4.tar.xz
==> Validating source files with sha256sums...
    rtmpdump-2.4.tar.xz ... Passed
==> Extracting Sources...
  -> Extracting rtmpdump-2.4.tar.xz with bsdtar
==> Removing existing pkg/ directory...
==> Starting build()...
make[1]: Entering directory `/home/rafael/builds/lib32-rtmpdump/src/rtmpdump-2.4/librtmp'
make[1]: Nothing to be done for `all'.
make[1]: Leaving directory `/home/rafael/builds/lib32-rtmpdump/src/rtmpdump-2.4/librtmp'
gcc -m32 -Wall   -DRTMPDUMP_VERSION=\"v2.4\"   -O2   -c -o rtmpdump.o rtmpdump.c
gcc -m32 -Wall  -o rtmpdump rtmpdump.o -L/usr/lib32-Llibrtmp -lrtmp -lssl -lcrypto -lz
/usr/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-unknown-linux-gnu/4.6.2/../../../librtmp.so when searching for -lrtmp
/usr/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-unknown-linux-gnu/4.6.2/../../../librtmp.a when searching for -lrtmp
/usr/bin/ld: skipping incompatible /usr/lib/librtmp.so when searching for -lrtmp
/usr/bin/ld: skipping incompatible /usr/lib/librtmp.a when searching for -lrtmp
/usr/bin/ld: cannot find -lrtmp
collect2: ld returned 1 exit status
make: *** [rtmpdump] Error 1
==> ERROR: A failure occurred in build().
    Aborting...