How can i change the shader?

[DeZhao-Zhang]

Platform:
Mapbox SDK version:

Steps to trigger behavior

while i change the line render in file src\mbgl\programs\gl\line.cpp, such as line.vertex.glsl or line.fragment.glsl.

Expected behavior

i hope while i change the color or gl_position, the actual render will be change,but no change happend. will i need to change other file, and generate the line.cpp file??

Actual behavior