I also faced this issue and this is how I fixed it:
ada-exp.y includes file
ada-lex.c which contains the definition for function
But if you don’t have flex installed initially, then it may generate an empty
ada-lex.l). And even if you do
make clean, it will not clean the generated
ada-lex.c, i.e., it will remain empty upon next compile command as well.
So to fix this error, you can delete all such intermediate
.c files (in your case, building with fresh
.tar.gz) and do the make again.
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