compilers: Don't add line comments to pre-processed output
compilers: Don't add line comments to pre-processed output

We never use preprocessed output anywhere except compiler checks,
so we don't care about the debugging information that it adds.
Just always disable it.

Closes https://github.com/mesonbuild/meson/issues/1726

MathieuDuponchelle/meson,becm/meson,aaronp24/meson,mesonbuild/meson,pexip/meson,mesonbuild/meson,becm/meson,ernestask/meson,trhd/meson,pexip/meson,wberrier/meson,QuLogic/meson,jeandet/meson,trhd/meson,ernestask/meson,ernestask/meson,becm/meson,MathieuDuponchelle/meson,MathieuDuponchelle/meson,QuLogic/meson,ernestask/meson,trhd/meson,rhd/meson,becm/meson,thiblahute/meson,thiblahute/meson,fmuellner/meson,mesonbuild/meson,thiblahute/meson,pexip/meson,jeandet/meson,jpakkane/meson,wberrier/meson,ernestask/meson,fmuellner/meson,aaronp24/meson,jeandet/meson,pexip/meson,jpakkane/meson,jpakkane/meson,thiblahute/meson,QuLogic/meson,thiblahute/meson,aaronp24/meson,fmuellner/meson,rhd/meson,pexip/meson,QuLogic/meson,MathieuDuponchelle/meson,becm/meson,becm/meson,trhd/meson,rhd/meson,ernestask/meson,mesonbuild/meson,fmuellner/meson,trhd/meson,mesonbuild/meson,jeandet/meson,jeandet/meson,thiblahute/meson,QuLogic/meson,trhd/meson,thiblahute/meson,rhd/meson,jeandet/meson,fmuellner/meson,MathieuDuponchelle/meson,aaronp24/meson,rhd/meson,jpakkane/meson,mesonbuild/meson,wberrier/meson,wberrier/meson,MathieuDuponchelle/meson,jpakkane/meson,becm/meson,jeandet/meson,wberrier/meson,aaronp24/meson,becm/meson,rhd/meson,fmuellner/meson,QuLogic/meson,jeandet/meson,wberrier/meson,aaronp24/meson,thiblahute/meson,pexip/meson,trhd/meson,pexip/meson,jpakkane/meson,ernestask/meson,trhd/meson,mesonbuild/meson,wberrier/meson,MathieuDuponchelle/meson,ernestask/meson,QuLogic/meson,aaronp24/meson,MathieuDuponchelle/meson,pexip/meson,mesonbuild/meson,fmuellner/meson,MathieuDuponchelle/meson,rhd/meson,pexip/meson,jeandet/meson,fmuellner/meson,becm/meson,trhd/meson,becm/meson,ernestask/meson,QuLogic/meson,mesonbuild/meson,QuLogic/meson,rhd/meson,pexip/meson,jpakkane/meson,jpakkane/meson,aaronp24/meson,aaronp24/meson,fmuellner/meson,jpakkane/meson,wberrier/meson,mesonbuild/meson,thiblahute/meson