configure script failure with SCO 5.0.7

I've been using postgresql 7.3.4 on SCO 5.0.7, with binaries installed as
part of SCO Update Pack 2 for 5.0.7.

GNU development tools include gcc 2.95.3p4, installed as supplied by SCO.

The cywwin build that I am using for development is 7.4.1-3 , and I would
like to run similar versions on both systems.

The configure script for the 7.4.2 source distribution fails as follows:

checking build system type... i386-pc-sco3.2v5.0.7
checking host system type... i386-pc-sco3.2v5.0.7
checking which template to use... sco
checking whether to build with 64-bit integer date/time support... no
checking whether NLS is wanted... no
checking for default port number... 5432
checking for gcc... gcc
checking for C compiler default output... a.out
checking whether the C compiler works... yes
checking whether we are cross compiling... no
checking for suffix of executables...
checking for suffix of object files... o
checking whether we are using the GNU C compiler... yes
checking whether gcc accepts -g... yes
checking how to turn off strict aliasing in gcc -b elf...
configure: using CFLAGS=-O2
checking whether the C compiler still works... no
configure: error: cannot proceed

Thanks,

David P. Lurie