Build nginx 1.19.7

[macbre]

Changes with nginx 1.19.7                                        16 Feb 2021

    *) Change: connections handling in HTTP/2 has been changed to better
       match HTTP/1.x; the "http2_recv_timeout", "http2_idle_timeout", and
       "http2_max_requests" directives have been removed, the
       "keepalive_timeout" and "keepalive_requests" directives should be
       used instead.

    *) Change: the "http2_max_field_size" and "http2_max_header_size"
       directives have been removed, the "large_client_header_buffers"
       directive should be used instead.

    *) Feature: now, if free worker connections are exhausted, nginx starts
       closing not only keepalive connections, but also connections in
       lingering close.

    *) Bugfix: "zero size buf in output" alerts might appear in logs if an
       upstream server returned an incorrect response during unbuffered
       proxying; the bug had appeared in 1.19.1.

    *) Bugfix: HEAD requests were handled incorrectly if the "return"
       directive was used with the "image_filter" or "xslt_stylesheet"
       directives.

    *) Bugfix: in the "add_trailer" directive.