configure: Enable compiling using -std=c11
configure: Enable compiling using -std=c11

On MinGW it remained gnu99, and may need (or not) to be changed too.

MadBomber/link-grammar,linas/link-grammar,opencog/link-grammar,MadBomber/link-grammar,linas/link-grammar,opencog/link-grammar,ampli/link-grammar,MadBomber/link-grammar,MadBomber/link-grammar,ampli/link-grammar,linas/link-grammar,ampli/link-grammar,opencog/link-grammar,opencog/link-grammar,opencog/link-grammar,opencog/link-grammar,linas/link-grammar,ampli/link-grammar,MadBomber/link-grammar,linas/link-grammar,ampli/link-grammar,MadBomber/link-grammar,ampli/link-grammar,MadBomber/link-grammar,opencog/link-grammar,opencog/link-grammar,linas/link-grammar,linas/link-grammar,ampli/link-grammar,MadBomber/link-grammar,opencog/link-grammar,ampli/link-grammar,linas/link-grammar,ampli/link-grammar,linas/link-grammar