compile error: parse error in common.h

[Lucas Fisher <ljfisher@iastate.edu>]

When compiling siag-3.3.0 I get the following error and warnings:
gcc - DHAVE_CONFIG_H -I. -I..        -Wall -g -O2 -c selection.c
In file included from selection.c:25:
../common/common.h:47: parse error before 'spawn'
../common/common.h:47: warning: type defaults to 'int' in declaration of
'spawn'
../common/common.h:47: warning: data definition has no type or storage
class

I'm running RH 6.1, but the problem has also been observed on Mandrake
7.0 (no surprise). gcc version is:
gcc version egcs-2.91.66 19990314/Linux (egcs-1.1.2 release)

thanks, 
Lucas