$ emerge taxbird
...
i686-pc-linux-gnu-gcc  -O2 -march=athlon-xp -fomit-frame-pointer -pipe     -Wl,--as-needed  -lguile -lguile-ltdl -lqthreads -lpthread -lcrypt -lm  -o taxbird  main.o console.o support.o interface.o callbacks.o workspace.o guile.o form.o dialog.o sigcheck.o export.o digest.o -pthread -L/usr/X11R6/lib -lgnomeui-2 -lSM -lICE -lbonoboui-2 -lgnome-keyring -lgnomecanvas-2 -lgnome-2 -lpopt -lart_lgpl_2 -lpangoft2-1.0 -lgnomevfs-2 -lbonobo-2 -lgconf-2 -lbonobo-activation -lORBit-2 -lgthread-2.0 -lgtkhtml-2 -lssl -lcrypto -lglade-2.0 -lgtk-x11-2.0 -lxml2 -lz -lgdk-x11-2.0 -latk-1.0 -lgdk_pixbuf-2.0 -lm -lpangocairo-1.0 -lpango-1.0 -lcairo -lgobject-2.0 -lgmodule-2.0 -ldl -lglib-2.0 -lgeier    -lgeier
main.o: In function `main':
main.c:(.text+0xa4): undefined reference to `scm_boot_guile'
main.o: In function `main_forward_catchy.1':
main.c:(.text+0x1c4): undefined reference to `gh_repl'
main.o: In function `main_forward':
main.c:(.text+0x262): undefined reference to `scm_internal_stack_catch'
main.c:(.text+0x294): undefined reference to `scm_internal_stack_catch'
console.o: In function `taxbird_console_init':
console.c:(.text+0x2b): undefined reference to `scm_c_define_gsubr'
console.o: In function `taxbird_console_select_template':
console.c:(.text+0xb4): undefined reference to `scm_num2int'
console.c:(.text+0xd4): undefined reference to `scm_makfrom0str'
console.c:(.text+0xe4): undefined reference to `scm_c_define'
console.c:(.text+0xff): undefined reference to `scm_c_define'
console.c:(.text+0x11a): undefined reference to `scm_c_define'
console.c:(.text+0x135): undefined reference to `scm_c_define'
console.c:(.text+0x150): undefined reference to `scm_c_define'
console.o:console.c:(.text+0x16b): more undefined references to `scm_c_define' follow
console.o: In function `taxbird_console_select_template':
console.c:(.text+0x199): undefined reference to `scm_call_0'
console.c:(.text+0x1a1): undefined reference to `scm_list_copy'
console.c:(.text+0x1b1): undefined reference to `scm_c_define'
console.c:(.text+0x1d7): undefined reference to `scm_makfrom0str'
workspace.o: In function `taxbird_ws_fill_tree_store':
workspace.c:(.text+0xd3): undefined reference to `scm_list_p'
workspace.c:(.text+0xea): undefined reference to `scm_ilength'
workspace.c:(.text+0xfa): undefined reference to `scm_ilength'
workspace.c:(.text+0x164): undefined reference to `scm_ilength'
workspace.c:(.text+0x172): undefined reference to `scm_list_p'
workspace.c:(.text+0x1ef): undefined reference to `gh_write'
workspace.o: In function `taxbird_ws_sel_form':
workspace.c:(.text+0x2f5): undefined reference to `scm_call_0'
workspace.c:(.text+0x338): undefined reference to `scm_call_0'
workspace.c:(.text+0x340): undefined reference to `scm_list_copy'
workspace.c:(.text+0x348): undefined reference to `scm_gc_protect_object'
workspace.o: In function `taxbird_ws_retrieve_field':
workspace.c:(.text+0x43e): undefined reference to `scm_makfrom0str'
workspace.c:(.text+0x47d): undefined reference to `scm_call_2'
workspace.c:(.text+0x4e4): undefined reference to `scm_makfrom0str'
workspace.c:(.text+0x521): undefined reference to `scm_call_2'
workspace.o: In function `taxbird_ws_sel_sheet':
workspace.c:(.text+0xca3): undefined reference to `scm_makfrom0str'
workspace.c:(.text+0xcba): undefined reference to `scm_call_1'
workspace.c:(.text+0xcc4): undefined reference to `scm_list_p'
workspace.c:(.text+0xcd3): undefined reference to `scm_ilength'
workspace.o: In function `taxbird_ws_store_event':
workspace.c:(.text+0xda1): undefined reference to `scm_makfrom0str'
workspace.c:(.text+0xded): undefined reference to `scm_makfrom0str'
workspace.c:(.text+0xeaa): undefined reference to `scm_call_3'
workspace.c:(.text+0x1011): undefined reference to `scm_int2num'
workspace.c:(.text+0x10ef): undefined reference to `scm_makfrom0str'
workspace.c:(.text+0x1238): undefined reference to `scm_take0str'
workspace.c:(.text+0x12bf): undefined reference to `scm_makfrom0str'
workspace.o: In function `taxbird_ws_open':
workspace.c:(.text+0x13df): undefined reference to `scm_makfrom0str'
workspace.c:(.text+0x13e9): undefined reference to `scm_makfrom0str'
workspace.c:(.text+0x13f5): undefined reference to `scm_open_file'
workspace.c:(.text+0x13fd): undefined reference to `scm_read_and_eval_x'
workspace.c:(.text+0x1407): undefined reference to `scm_list_p'
workspace.c:(.text+0x1416): undefined reference to `scm_ilength'
workspace.c:(.text+0x1480): undefined reference to `scm_gc_protect_object'
workspace.o: In function `taxbird_ws_save':
workspace.c:(.text+0x15b2): undefined reference to `scm_makfrom0str'
workspace.c:(.text+0x15c0): undefined reference to `scm_makfrom0str'
workspace.c:(.text+0x15cc): undefined reference to `scm_open_file'
workspace.c:(.text+0x15da): undefined reference to `scm_makfrom0str'
workspace.c:(.text+0x15e6): undefined reference to `scm_display'
workspace.c:(.text+0x161a): undefined reference to `scm_makfrom0str'
workspace.c:(.text+0x1626): undefined reference to `scm_list_2'
workspace.c:(.text+0x1632): undefined reference to `scm_write'
workspace.c:(.text+0x163a): undefined reference to `scm_close'
workspace.o: In function `taxbird_ws_chooser_additem':
workspace.c:(.text+0x175f): undefined reference to `scm_makfrom0str'
workspace.c:(.text+0x176d): undefined reference to `scm_makfrom0str'
workspace.c:(.text+0x177b): undefined reference to `scm_c_lookup'
workspace.c:(.text+0x17a1): undefined reference to `scm_error_scm'
workspace.o: In function `taxbird_ws_unprotect_scm':
workspace.c:(.text+0x1721): undefined reference to `scm_gc_unprotect_object'
guile.o: In function `taxbird_guile_dirlist_lookup':
guile.c:(.text+0x15): undefined reference to `scm_c_lookup'
guile.c:(.text+0x7d): undefined reference to `scm_ilength'
guile.o: In function `taxbird_guile_eval_file':
guile.c:(.text+0x17d): undefined reference to `scm_c_primitive_load'
guile.o: In function `taxbird_guile_init':
guile.c:(.text+0x1dc): undefined reference to `scm_makfrom0str'
guile.c:(.text+0x1e6): undefined reference to `scm_take0str'
guile.c:(.text+0x1f4): undefined reference to `scm_makfrom0str'
guile.c:(.text+0x202): undefined reference to `scm_makfrom0str'
guile.c:(.text+0x216): undefined reference to `scm_list_4'
guile.c:(.text+0x226): undefined reference to `scm_c_define'
guile.c:(.text+0x232): undefined reference to `scm_int2num'
guile.c:(.text+0x242): undefined reference to `scm_c_define'
guile.c:(.text+0x24e): undefined reference to `scm_int2num'
guile.c:(.text+0x25e): undefined reference to `scm_c_define'
guile.c:(.text+0x26a): undefined reference to `scm_int2num'
guile.c:(.text+0x27a): undefined reference to `scm_c_define'
guile.c:(.text+0x286): undefined reference to `scm_int2num'
guile.c:(.text+0x296): undefined reference to `scm_c_define'
guile.c:(.text+0x2a2): undefined reference to `scm_int2num'
guile.c:(.text+0x2b2): undefined reference to `scm_c_define'
guile.c:(.text+0x2be): undefined reference to `scm_int2num'
guile.c:(.text+0x2ce): undefined reference to `scm_c_define'
guile.c:(.text+0x2fa): undefined reference to `scm_c_define_gsubr'
guile.c:(.text+0x326): undefined reference to `scm_c_define_gsubr'
guile.c:(.text+0x352): undefined reference to `scm_c_define_gsubr'
guile.c:(.text+0x37e): undefined reference to `scm_c_define_gsubr'
guile.c:(.text+0x3aa): undefined reference to `scm_c_define_gsubr'
guile.o:guile.c:(.text+0x3d6): more undefined references to `scm_c_define_gsubr' follow
guile.o: In function `taxbird_guile_check_sig_SCM':
guile.c:(.text+0x545): undefined reference to `scm_take0str'
guile.c:(.text+0x553): undefined reference to `scm_take0str'
guile.c:(.text+0x55f): undefined reference to `scm_list_2'
guile.o: In function `taxbird_guile_global_err_handler':
guile.c:(.text+0x5a0): undefined reference to `scm_backtrace'
guile.c:(.text+0x5bc): undefined reference to `scm_handle_by_message_noexit'
guile.o: In function `taxbird_dialog_error_SCM':
guile.c:(.text+0x5f2): undefined reference to `scm_makfrom0str'
guile.c:(.text+0x600): undefined reference to `scm_makfrom0str'
guile.c:(.text+0x60e): undefined reference to `scm_c_lookup'
guile.c:(.text+0x634): undefined reference to `scm_error_scm'
guile.o: In function `taxbird_dialog_info_SCM':
guile.c:(.text+0x692): undefined reference to `scm_makfrom0str'
guile.c:(.text+0x6a0): undefined reference to `scm_makfrom0str'
guile.c:(.text+0x6ae): undefined reference to `scm_c_lookup'
guile.c:(.text+0x6d4): undefined reference to `scm_error_scm'
guile.o: In function `taxbird_get_version':
guile.c:(.text+0x71b): undefined reference to `scm_makfrom0str'
guile.o: In function `taxbird_activate_sheet':
guile.c:(.text+0x756): undefined reference to `scm_makfrom0str'
guile.c:(.text+0x764): undefined reference to `scm_makfrom0str'
guile.c:(.text+0x772): undefined reference to `scm_c_lookup'
guile.c:(.text+0x798): undefined reference to `scm_error_scm'
form.o: In function `taxbird_form_register':
form.c:(.text+0x131): undefined reference to `scm_gc_protect_object'
form.c:(.text+0x14e): undefined reference to `scm_gc_protect_object'
form.c:(.text+0x16b): undefined reference to `scm_gc_protect_object'
form.c:(.text+0x188): undefined reference to `scm_gc_protect_object'
form.c:(.text+0x1a5): undefined reference to `scm_gc_protect_object'
form.o:form.c:(.text+0x1c2): more undefined references to `scm_gc_protect_object' follow
form.o: In function `taxbird_form_register':
form.c:(.text+0x1e9): undefined reference to `scm_int2num'
export.o: In function `taxbird_export_bottom_half':
export.c:(.text+0x229): undefined reference to `scm_take_str'
export.o: In function `taxbird_export':
export.c:(.text+0xb4b): undefined reference to `scm_call_2'
export.c:(.text+0xb55): undefined reference to `scm_list_p'
export.c:(.text+0xb74): undefined reference to `scm_c_lookup'
export.c:(.text+0xb86): undefined reference to `scm_call_1'
export.c:(.text+0xd92): undefined reference to `scm_c_lookup'
export.c:(.text+0xda4): undefined reference to `scm_call_1'
export.c:(.text+0xde6): undefined reference to `scm_gc_protect_object'
export.c:(.text+0xe00): undefined reference to `scm_gc_unprotect_object'
collect2: ld gab 1 als Ende-Status zurück
make[4]: *** [taxbird] Fehler 1
make[4]: Leaving directory `/var/tmp/portage/taxbird-0.7/work/taxbird-0.7/src'
make[3]: *** [all-recursive] Fehler 1
make[3]: Leaving directory `/var/tmp/portage/taxbird-0.7/work/taxbird-0.7/src'
make[2]: *** [all] Fehler 2
make[2]: Leaving directory `/var/tmp/portage/taxbird-0.7/work/taxbird-0.7/src'
make[1]: *** [all-recursive] Fehler 1
make[1]: Leaving directory `/var/tmp/portage/taxbird-0.7/work/taxbird-0.7'
make: *** [all] Fehler 2

!!! ERROR: app-office/taxbird-0.7 failed.
Call stack:
  ebuild.sh, line 1539:   Called dyn_compile
  ebuild.sh, line 939:   Called src_compile
  taxbird-0.7.ebuild, line 38:   Called die

!!! Make failed!
!!! If you need support, post the topmost build error, and the call stack if relevant.