The previous commit accidentally introduced the literal 2-byte sequence
'\r' at the end of two backslash-continuation lines (TESTS_STANDALONE
and the .PHONY list). GNU make on Linux treats that as text rather than
a line continuation, which orphans the following line with leading
spaces and aborts CI with:
Makefile:68: *** missing separator (did you mean TAB instead of 8 spaces?)
Strip the extraneous 'r' so each continuation ends with a real backslash
+ LF.