OpenGroupWare build failed

[Kliment Andreev]

I am trying to build OpenGroupware from sources.

Using:
FreeBSD 4.7
GNU Make 3.79.1
gcc 2.95.4

Everything went fine until I've tried to build SKYRIX Core Libraires

# gmake -s nosasl=yes debug=yes install
....
NGActiveSocket.m: In function `-[NGActiveSocket _unixWriteBytes:count:]':
NGActiveSocket.m:860: warning: implicit declaration of function `sleep'
gmake[2]: *** [shared_debug_obj/ix86/freebsd/gnu-fd-nil/NGActiveSocket.o]
Error 1
gmake[1]: *** [libNGStreams.all.library.variables] Error 2
gmake: *** [internal-all] Error 2


I tried to find what this error means but there is no explanation on GNU
Make site. I assume that the problem is the linker.

Anyone?

Thanks...