shell saying "not found" for a command within a makefile

Question

When defining a command as a constant within a Makefile:

MY_COMMANDLINE="prog arg1 arg2"

and using this constant later to get the command invoked, you could get:

/bin/sh: prog arg1 arg2: not found

although prog definitely exists.
Explicitly giving the whole path of prog does not help.

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Answer 1

Unlike e.g. in shell scripts the quotes become part of the string and get transferred to the shell, which obviously then searches for the whole path incl. all spaces.

Defining the command line without quotes:

MY_COMMANDLINE=prog arg1 arg2

works.