problems compiling on solaris

Hello all,

I'm trying to compile pg7.4.1 on Solaris using the Sun compilers.   All
works fine except that I get this error in tuptoaster.c:

cc -Xa -fast -I../../../../src/include -I/usr/local/ren/prod/include/
-c -o tuptoaster.o tuptoaster.c
cc: Warning: -xarch=native has been explicitly specified, or implicitly
specified by a macro option, -xarch=native on this architecture implies
-xarch=v8plusb which generates code that does not run on pre UltraSPARC
III processors
"tuptoaster.c", line 831: member can not have variably modified type: data
cc: acomp failed for tuptoaster.c
gmake: *** [tuptoaster.o] Error 2


What am I missing?  This happens when simply doing a
CC=cc ./configure; gmake

Thanks!

-- Alan