Using libcurl autoconf curl-config
curl / libcurl / Using / libcurl.m4 - autoconf macro

libcurl.m4 - autoconf macro for detecting libcurl

Related:
curl-config

On unix-like systems, configure scripts are used to detect and check system information. These scripts are generally built with Autoconf.

If you write a program that depends on a certain version of libcurl, you might find libcurl.m4 useful to detect libcurl.