Building 4.1.0 rc1 on Solaris 10 with Sun Workshop 8 cc

A libiberty problem on an almost-GA-build of Solaris 10:

cvs co -r gnats-4_1_0-rc1 gnats
CC=/opt/SUNWspro8/bin/cc ./configure
gmake stops with the following:

--------------------------
/opt/SUNWspro8/bin/cc -c -DHAVE_CONFIG_H -g -I. -I./../include 
sigsetmask.c -o sigsetmask.o
"/usr/include/sys/feature_tests.h", line 329: #error: "Compiler or 
options invalid for pre-UNIX 03 X/Open applications  and pre-2001 POSIX 
applications"
cc: acomp failed for sigsetmask.c
gmake[1]: *** [sigsetmask.o] Error 2
gmake[1]: Leaving directory 
`/home/ys136781/gnats/gnats-4.1.0rc1/gnats/libiberty'
gmake: *** [libiberty/libiberty.a] Error 2
--------------------------

Yngve Svendsen
Gnatsweb maintainer