Not in Portugal, we were using mostly using Turbo Pascal.
In the 80's using C on MS-DOS, was only seen by those that had UNIX at work or universities and wanted to work home.
It wasn't even C, rather SmallC or any other K&R dialect.
In any case, everyone that cared about performance was using TASM and MASM, writing everything in Assembly.
Lots of Pascal, but Pascal really was an engineering constraint at the time if you were doing actual system programming. And back then, that was a serious consideration.