devel/libvirt: update to 4.3.0

• Update to 4.3.0,
• Chase a change in libintl detection by removing no longer functional '--with-libintl-prefix' configure flag and setting CFLAGS appropriately,
• Remove trailing whitespace from pkg-plist [1],
• Update website [1].

PR: 227883 [1]
Submitted by: 0mp [1]