make -C docs/cmdline-opts install depends on all-am, which in turn
depends on $(MANS), unconditionally defined to be $(man_MANS).
As with CLEANFILES, only add curl.1 to man_MANS when BUILD_DOCS is true
so we don't try to build curl.1 unnecessarily.
Closes#13198
You find a mix of various documentation in this directory and subdirectories,
using several different formats. Some of them are not ideal for reading
directly in your browser.
If you would rather see the rendered version of the documentation, check out the
curl website's documentation section for
general curl stuff or the libcurl section for
libcurl related documentation.