Can't compile JPilot on Slackware 12

[Ralph Alvy]

I get errors like the following when attempting to compile 0.99.9 under 
Slackware 12. Is this a Slackware problem or a JPilot problem? ...

jpilot.c:1773: error: expected '=', ',', ';', 'asm' or '__attribute__' 
before '{' token
jpilot.c:1891: error: expected '=', ',', ';', 'asm' or '__attribute__' 
before '{' token
jpilot.c:1912: error: expected '=', ',', ';', 'asm' or '__attribute__' 
before '{' token
jpilot.c:1939: error: expected '=', ',', ';', 'asm' or '__attribute__' 
before '{' token
jpilot.c:2906: error: expected '=', ',', ';', 'asm' or '__attribute__' 
before '{' token
jpilot.c:2908: error: old-style parameter declarations in prototyped
function 
definition
/usr/include/X11/Xlib.h:3571: error: parameter name omitted
jpilot.c:2908: error: expected '{' at end of input
make[2]: *** [jpilot.o] Error 1
make[2]: Leaving directory `/home/ralvy/jpilot-0.99.9'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/home/ralvy/jpilot-0.99.9'
make: *** [all] Error 2