The runtest script converts a relative name of the binary to an
absolute name. This is mainly a comfort feature.
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# If the first character of the first argument is '/', the argument is taken
-# as the path to the binary.
+# as the path to the binary. If the first argument does not start with a
+# '/' but exists in the file system, it's assumed to be the Exim binary.
-$parm_exim = (@ARGV > 0 && $ARGV[0] =~ m?^/?)? shift @ARGV : "";
+$parm_exim = (@ARGV > 0 && (-x $ARGV[0] or $ARGV[0] =~ m?^/?))? Cwd::abs_path(shift @ARGV) : "";
print "Exim binary is $parm_exim\n" if $parm_exim ne "";