Build failure on Solaris 10 with Sun cc

[Paul Eggert]

Here are the symptoms:

source='b-divvy.c' object='b-divvy.o' libtool=no \
DEPDIR=.deps depmode=none /bin/bash ../build-aux/depcomp \
cc -xc99=all -xc99=all -DHAVE_CONFIG_H -I. -I../lib  -I'../lib'    -g -c b-divv\
y.c
"b-divvy.c", line 91: left operand of "->" must be pointer to struct/union
"b-divvy.c", line 91: left operand of "->" must be pointer to struct/union
"b-divvy.c", line 91: left operand of "->" must be pointer to struct/union
"b-divvy.c", line 91: left operand of "->" must be pointer to struct/union
"b-divvy.c", line 91: left operand of "->" must be pointer to struct/union
"b-divvy.c", line 91: left operand of "->" must be pointer to struct/union
...

A lot more messages came out, much like the previous ones shown above,
and the compilation failed.