GLSL not a good fit for Unity on PC

I have decided to write my shader in HLSL/Cg rather than GLSL. On my Windows PC, Unity assumes that I that the GLSL I am writing is version 4 (that my graphics card supports) but can’t compile as all the resources I find are based on GLSL version 1.3 or lower but as of 1.4 the oft-used type qualifiers attribute and varying were removed. My Android device has OpenGL ES 2.0 hardware which supports only GLSL version 1.1 and parts of 1.2. That means the same code will not run on both my PC for debugging purposes and on my Android device. I have only been able to make simple shaders without portability problems. Also, Unity does not recommend writing directly in GLSL. The Unity editor crashed and froze many times without producing helpful debug messages about the GLSL code errors.