Postgres Installation

When installing Postgres 7.1rc4 on Solaris 7, I get the following error
on make:
gcc  -Wall -Wmissing-prototypes -Wmissing-declarations
-I../../../../src/include
   -c filename.c -o filename.o
I can't do a regression test -there is no pgsql folder in /usr/src - and
of course createdb doesn't work after make install

Help!

Christine