Вот решил прикрутить PPPD к серверу и при попытке собрать плагин libtraffpro.so получил следующее:

/traffpro.pppd/Debug# make
Building file: ../config.c
Invoking: GCC C Compiler
gcc -O0 -g3 -Wall -c -fmessage-length=0 -fPIC -MMD -MP -MF"config.d" -MT"config. d" -o"config.o" "../config.c"
Finished building: ../config.c

Building file: ../strfunct.c
Invoking: GCC C Compiler
gcc -O0 -g3 -Wall -c -fmessage-length=0 -fPIC -MMD -MP -MF"strfunct.d" -MT"strfu nct.d" -o"strfunct.o" "../strfunct.c"
../strfunct.c: In function 'read_accept_ports':
../strfunct.c:24: warning: implicit declaration of function 'isdigit'
Finished building: ../strfunct.c

Building file: ../traffpro.c
Invoking: GCC C Compiler
gcc -O0 -g3 -Wall -c -fmessage-length=0 -fPIC -MMD -MP -MF"traffpro.d" -MT"traff pro.d" -o"traffpro.o" "../traffpro.c"
In file included from ../traffpro.c:12:
../traffpro.h:39:23: warning: pppd/pppd.h: No such file or directory
../traffpro.h:40:22: warning: pppd/fsm.h: No such file or directory
../traffpro.h:41:23: warning: pppd/ipcp.h: No such file or directory
../traffpro.h:43:27: warning: pppd/chap-new.h: No such file or directory
../traffpro.h:44:22: warning: pppd/md5.h: No such file or directory
In file included from ../traffpro.c:12:
../traffpro.h:59: warning: 'struct chap_digest_type' declared inside parameter l ist
../traffpro.h:59: warning: its scope is only this definition or declaration, whi ch is probably not what you want
In file included from ../traffpro.c:12:
../traffpro.h:60: warning: 'struct wordlist' declared inside parameter list
../traffpro.c:19: error: 'MAXNAMELEN' undeclared here (not in a function)
../traffpro.c:82: error: expected '=', ',', ';', 'asm' or '__attribute__' before 'options'
../traffpro.c: In function 'init_db':
../traffpro.c:117: warning: implicit declaration of function 'info'
../traffpro.c: In function 'logout_client':
../traffpro.c:238: warning: implicit declaration of function 'update_link_stats'
../traffpro.c:286: error: 'link_stats' undeclared (first use in this function)
../traffpro.c:286: error: (Each undeclared identifier is reported only once
../traffpro.c:286: error: for each function it appears in.)
../traffpro.c: In function 'get_chap_password':
../traffpro.c:426: warning: implicit declaration of function 'ip_ntoa'
../traffpro.c:426: error: 'ipcp_wantoptions' undeclared (first use in this funct ion)
../traffpro.c:426: warning: assignment makes pointer from integer without a cast
../traffpro.c:357: warning: unused variable 'count_record'
../traffpro.c: In function 'get_password_hook':
../traffpro.c:521: error: 'ipcp_wantoptions' undeclared (first use in this funct ion)
../traffpro.c:521: warning: assignment makes pointer from integer without a cast
../traffpro.c: At top level:
../traffpro.c:653: warning: 'struct wordlist' declared inside parameter list
../traffpro.c:652: error: conflicting types for 'get_pap_auth_hook'
../traffpro.h:60: note: previous declaration of 'get_pap_auth_hook' was here
../traffpro.c: In function 'get_pap_auth_hook':
../traffpro.c:668: error: invalid application of 'sizeof' to incomplete type 'st ruct wordlist'
../traffpro.c:670: error: dereferencing pointer to incomplete type
../traffpro.c:670: error: invalid use of undefined type 'struct wordlist'
../traffpro.c:671: error: dereferencing pointer to incomplete type
../traffpro.c:673: warning: implicit declaration of function 'BCOPY'
../traffpro.c:673: error: dereferencing pointer to incomplete type
../traffpro.c: At top level:
../traffpro.c:699: warning: 'struct chap_digest_type' declared inside parameter list
../traffpro.c:697: error: conflicting types for 'get_chap_verify'
../traffpro.h:59: note: previous declaration of 'get_chap_verify' was here
../traffpro.c: In function 'get_chap_verify':
../traffpro.c:715: error: dereferencing pointer to incomplete type
../traffpro.c:717: error: 'user' undeclared (first use in this function)
../traffpro.c:718: warning: implicit declaration of function 'error'
../traffpro.c: At top level:
../traffpro.c:799: warning: 'struct ppp_idle' declared inside parameter list
../traffpro.c: In function 'time_hook':
../traffpro.c:832: warning: implicit declaration of function 'die'
../traffpro.c: In function 'plugin_init':
../traffpro.c:854: warning: implicit declaration of function 'add_options'
../traffpro.c:854: error: 'options' undeclared (first use in this function)
../traffpro.c:911: warning: implicit declaration of function 'add_notifier'
../traffpro.c:911: error: 'link_down_notifier' undeclared (first use in this fun ction)
../traffpro.c:912: error: 'exitnotify' undeclared (first use in this function)
../traffpro.c:918: error: 'chap_passwd_hook' undeclared (first use in this funct ion)
../traffpro.c:919: error: 'chap_check_hook' undeclared (first use in this functi on)
../traffpro.c:920: error: 'chap_verify_hook' undeclared (first use in this funct ion)
../traffpro.c:922: error: 'pap_check_hook' undeclared (first use in this functio n)
../traffpro.c:923: error: 'pap_logout_hook' undeclared (first use in this functi on)
../traffpro.c:924: error: 'pap_auth_hook' undeclared (first use in this function )
../traffpro.c:926: error: 'snoop_recv_hook' undeclared (first use in this functi on)
../traffpro.c:927: error: 'snoop_send_hook' undeclared (first use in this functi on)
../traffpro.c:930: error: 'idle_time_hook' undeclared (first use in this functio n)
../traffpro.c:937: error: 'ip_choose_hook' undeclared (first use in this functio n)
../traffpro.c:938: error: 'allowed_address_hook' undeclared (first use in this f unction)
make: *** [traffpro.o] Error 1

Скриптом ./create_lib.sh результат аналогичный... подскажите где могут быть грабли?
Ubuntu 9.10, Traffpro office 1.3.8

УВас просто пакета ppp-dev не установлено.

странно, точно помню что был

Так обычно если нет заголовочных, проверьте есть они в /usr/include/pppd/ ?

Действительно, вы оказались правы, ppp-dev не был установлен