in m4's patsubst, how do I replace newlines with spaces?

问题

How can I tell m4's patsubstr to replace all newlines in a string with a space?

I've tried:

patsubst(MULTI_LINE_STR_DEFINE,`\n',` ')

and

patsubst(MULTI_LINE_STR_DEFINE,`\\n',` ')

回答1:

patsubst(MULTI_LINE_STR_DEFINE,`
',` ')

That is, you put the newline, literally, between quotes.

来源：https://stackoverflow.com/questions/1567668/in-m4s-patsubst-how-do-i-replace-newlines-with-spaces