I cloned from http://hg.nginx.org/nginx to try and reproduce with your configure arguments, but i actually error out elsewhere;

    src/http/ngx_http_request.c: In function ‘ngx_http_set_virtual_server’:
    src/http/ngx_http_request.c:1955:32: error: ‘cscf’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
    cc1: all warnings being treated as errors

which i'm not interested in following up. My `ngx_string.o` did build successfully though. Using gcc 4.7.2 on Debian 7

Are you using a new CPU with an old(er) gcc version? Try specifying -march explicitly instead of native.