[PATCH v2] block/curl.c: Use explicit long constants in curl_easy_setopt calls

[Richard W.M. Jones]

v1 was posted here:
https://patchwork.ozlabs.org/project/qemu-devel/patch/20251001124055.2743244-1-rjo...@redhat.com/

In v2, I incorporated additional changes found by Chenxi Mao.

Rich.