libX11 1.8.7

• Security fixes and hardening in XImage and pixmap handling code (CVE-2023-43786, CVE-2023-43787, !234 (merged))
• Fix buffer allocation in _XkbReadKeySyms() (CVE-2023-43785)
• Fail XOpenDisplay() if server-provided default visual is invalid (!233 (merged))
• Bring XKB docs in line with actual implementation (!231 (merged), !228 (merged))
• Xutil.h: declare XEmptyRegion() and XEqualRegion() as Bool (!225 (merged))
• Assorted updates to en_US.UTF-8 compose keys (!213 (merged), !214 (merged), !215 (merged), !216 (merged), !217 (merged), !219 (merged), !220 (merged), !222 (merged), !223 (merged), !226 (merged), !227 (merged), !229 (merged))