QShaderGenerator: Allow more expressions in input nodes

Currently QShaderGenerator will crash when encountering some expressions
in input nodes.

For example, this node prototype would make it crash:
"VERTEX_COLOR": {
  "outputs": ["color", "alpha"],
  "rules": [
    "headerSnippets": ["in vec4 vertexColor;"],
    "substitution": "vec3 $color = vertexColor.rgb;
                     float $alpha = vertexColor.a;"
  ]
}

Change-Id: I37abb8099d376843a4cb13228140467dc1b8f60c
Reviewed-by: Paul Lemire <paul.lemire@kdab.com>
(cherry picked from commit f9086ebd0198c53e8a811af47e0ff0c84d78eb30)

0 files changed, 0 insertions, 0 deletions