compile problem with gcc 2.95

I know it's an ancient compiler, but last time I checked it is still
faster at runtime than the 3.x versions.  If it's not going to be
supported, it would probably be nice to at least detect that in the
build system.  I've confirmed that it works just fine with gcc 3.3.

dave@spirit:~/bin/git$ make
gcc -o rev-cache.o -c -g -O2 -Wall '-DSHA1_HEADER=<openssl/sha.h>'
rev-cache.c
In file included from rev-cache.c:2:
cache.h:107: field `name' has incomplete type
cache.h:290: field `base' has incomplete type
cache.h:303: field `pack_name' has incomplete type
cache.h:318: field `name' has incomplete type
make: *** [rev-cache.o] Error 1
dave@spirit:~/bin/git$ gcc -v
Reading specs from /usr/lib/gcc-lib/i386-linux/2.95.4/specs
gcc version 2.95.4 20011002 (Debian prerelease)

struct cache_entry {

...

        char name[]; <--- cache.h:107
};

-- Dave