Compiling error in PAM

hi,

i try to compile 5.2 (cvsed) on a 5.1 machine. When i do so i get this error:

/usr/src/lib/libpam/modules/pam_echo/pam_echo.c: In function `_pam_echo':
/usr/src/lib/libpam/modules/pam_echo/pam_echo.c:92: warning: dereferencing type-punned pointer will break strict-aliasing rules
*** Error code 1


any idea's?