bug#43666: [grep-3.5] make failed on Solaris 11.3 x86/x64

[Kiyoshi KANAZAWA]

Hi, Paul,

I confirmed.
All the tests passed with every combination of (gcc 9.3.0, developerstudio12.6) 
& (-m32, -m64) on Solaris11.3 x86/x64.
Segmentation Fault & Abort disappeared from triple-backref.

Thank you.

--- Kiyoshi