I think this is simply a general c++ question:
I\'m attempting to compile a local version of ffmpeg on Linux Fedora using the gnu c++ compiler. I have source code in
It should be the first one --prefix=/usr/local but to install files in that location you need root privileges. So you need to either change to the root account su or use sudo if you are a sudo user aka sudo make install. Only do that for the install phase, don't build like that.
Also /usr/local is usually the default install location so you don't usually need to specify that. Normally you only use --prefix to install into a different location like --prefix=/opt or your home folders: --prefix=$HOME/3rdparty.
Incidentally, if you install into your home folder you won't need root privileges.