lexer: Fix negative 'n0' and 'n1' in lex_source_contains_macro_call().
[pspp] / tests / ui /
drwxr-xr-x   ..
-rw-r--r-- 1810 syntax-gen-test.c
-rw-r--r-- 1406 syntax-gen.at
drwxr-xr-x - terminal