binutils: Enable --with-sysroot=/ for Linuxbrew
Linuxbrew: Need quotes around bottle_tag
Linuxbrew: Add [-0-9] to BOTTLE_EXTNAME_RX

Change [a-z_]+(32)? to [-a-z0-9_]+
The Linuxbrew bottle tag is x86_64-linux.
Linuxbrew: Add the SourceForge URL
linux-headers: Remove .install and ..install.cmd
linux-headers: add 3.15.9 bottle.