pigeon% ./configure --enable-pthread
checking build system type... i686-pc-linux
[...]
checking for nanosleep... yes
[...]
config.status: creating Makefile
pigeon% 
    
pigeon% grep NANOSLEEP *
configure:#define HAVE_NANOSLEEP 1
configure.in:       AC_CHECK_LIB(rt, nanosleep, AC_DEFINE(HAVE_NANOSLEEP))
eval.c:#ifdef HAVE_NANOSLEEP
pigeon%     

pigeon% grep \(nanosleep configure.in
   AC_CHECK_FUNC(nanosleep)
pigeon% 

 perhaps best to use AC_CHECK_FUNCS


Guy Decoux