Fixes Oss-Fuzz issue: 21916 (open-source-parsers#1180)

* Fix heap-buffer-overflow in json_reader

BORLAND compatible

1.8.4; soversion=20

Merge pull request open-source-parsers#655 from cdunn2001/fix-649

Fixes open-source-parsers#649
Fixes open-source-parsers#654

Merge pull request open-source-parsers#652 from cdunn2001/meson-not-s…

…cons

Meson not scons; 1.8.2<-1.8.1

Require cmake>=3.1

Plus some other build-related changes. I don't think there is anything
functionally different from 1.7.7, or even any binary incompatibilities, but
the cmake change is significant.

1.7.6 <- 1.7.5

1.7.5 <- 1.7.4