Curl build issue causing problematic file size growth fixed

[Ilmari Lauhakangas]

Last year a new developer faced a nasty build issue with a Curl makefile 
growing to fill all the available disk space. After reporting it to 
Curl, I learned it was known since at least 2021 and it was suspected to 
be an automake regression.

In the end, it turned out that we had barked up the wrong tree and 
automake contributor Jan Engelhardt was kind enough to provide a fix in 
Curl:

https://github.com/curl/curl/commit/73e9e6d767296c5759972d07f2441c8993ccbb9d

There will be no new point releases of Curl 7, so the fix will be 
shipped in version 8.

Ilmari