This bug will occur on all unix systems (linux, solaris, etc.)

keysymdef.h contains some keysyms for dead keys that are missing from
the translation table in canvas.c. I suspect that we need to add these
in order to fix bugs such as 4420581.

Here is some data from /usr/include/X11/keysymdef.h

#define XK_dead_grave 0xFE50
#define XK_dead_acute 0xFE51
#define XK_dead_circumflex 0xFE52
#define XK_dead_tilde 0xFE53
#define XK_dead_macron 0xFE54
#define XK_dead_breve 0xFE55
#define XK_dead_abovedot 0xFE56
#define XK_dead_diaeresis 0xFE57
#define XK_dead_abovering 0xFE58
#define XK_dead_doubleacute 0xFE59
#define XK_dead_caron 0xFE5A
#define XK_dead_cedilla 0xFE5B
#define XK_dead_ogonek 0xFE5C
#define XK_dead_iota 0xFE5D
#define XK_dead_voiced_sound 0xFE5E
#define XK_dead_semivoiced_sound 0xFE5F

Some more entries in /usr/openwin/lib/X11/XKeysymDB

SunFA_Grave :1005FF00
SunFA_Circum :1005FF01
SunFA_Tilde :1005FF02
SunFA_Acute :1005FF03
SunFA_Diaeresis :1005FF04
SunFA_Cedilla :1005FF05
SunF36 :1005FF10
SunF37 :1005FF11
SunSys_Req :1005FF60
SunProps :1005FF70
SunFront :1005FF71
SunCopy :1005FF72
SunOpen :1005FF73
SunPaste :1005FF74
SunCut :1005FF75

SunCompose :FF20
SunPageUp :FF55
SunPageDown :FF56
SunPrint_Screen :FF61
SunUndo :FF65
SunAgain :FF66
SunFind :FF68
SunStop :FF69
SunAltGraph :FF7E

There are some osf entries in the same file, along with several others.