graphics/libgphoto2: the port had been updated to version 2.5.31

• Clean up USES list (no longer requires GNU make, etc.)
• Do not set USE_CSTD, GNU_CONFIGURE_MANPREFIX, and particularly CONFIGURE_ENV which could break the build (doxygen-related)
• Drop old patches and sed(1) fixup that are no longer needed

PR: 277551
Reported by: portscout