1make: "varmod-shell.mk" line 25: warning: while evaluating "${:!echo word; (exit 13)!} != "word"" with value "word": Command "echo word; (exit 13)" exited with status 13 2make: "varmod-shell.mk" line 29: warning: while evaluating "${:Uprevious value:!echo word; (exit 13)!} != "word"" with value "word": Command "echo word; (exit 13)" exited with status 13 3Global: _ = # (empty) 4Var_Parse: ${:!echo word; ${:U(exit 13)}!} (eval-keep-dollar-and-undefined) 5Evaluating modifier ${:!...} on value "" (eval-keep-dollar-and-undefined, undefined) 6Modifier part: "echo word; (exit 13)" 7Capturing the output of command "echo word; (exit 13)" 8make: "varmod-shell.mk" line 36: warning: while evaluating "${:!echo word; ${:U(exit 13)}!}" with value "word": Command "echo word; (exit 13)" exited with status 13 9Result of ${:!echo word; ${:U(exit 13)}!} is "word" (eval-keep-dollar-and-undefined, defined) 10Global: _ = word 11Global: .MAKEFLAGS = -r -k -d v -d 12Global: .MAKEFLAGS = -r -k -d v -d 0 13exit status 0 14