x11/alttab: Update to 1.8.0

ChangeLog: https://github.com/sagb/alttab/releases/tag/v1.8.0

• Disable bottom line by default.
• Avoid xnee dependency in tests.
• Build variable to debug icon source.
• More secure input filtering.
• Option -s 5 to prefer file icon if size is equal.
• Escape key to close UI.
• Handle COMPOUND WM_NAME.
• Secure window name loading in ratpoison.
• Show desktop names instead of numbers.
• Adapt test script for Darwin.
• Option -sortmin to show minimized windows last.
• Option -min to color minimized windows frames.
• Fix DISPLAY in test script.
• Fix C language errors.

Reported by: portscout

(cherry picked from commit 10844f82f88ea31e75d5633e34712297cf56a4b9)