qsb generates shader that webassembly does not accept

The project

qtdeclarative\examples\quick\scenegraph\custommaterial

does not run on the webassembly platform because a for loop is rewritten to skip

the init part.

code in question:

file shaders\mandelbrot.frag

...

int i;

for (i = 0; i < ubuf.limit; i++) {

...

rewritten to

int i = 0;

for (; i < ubuf.limit; i++) {