Incorrect use of $ when getting relative directory

[m8pple]

Somebody pointed out (sorry, I've forgotten who), that there is a problem in the
instructions for getting the relative directory. What I've suggested is doing this:

./configure --prefix="$(pwd)/../../local"

This works fine in the shell, but what I didn't consider is what happens inside
the makefile.

Inside the makefile, $ means "macro expansion", and $(X) means look
for makefile variable called X. I managed to introduce this bug as a
regression in this commit: d43cbb6. The aim was to make things simpler, but I didn't test properly.

Potential solutions are:

Use back-tick syntax

In the shell, the syntax:

`pwd`

is equivalent to

$(pwd)

so you can use:

./configure --prefix="`pwd`/../../local"

in the makefile or on the command line.

Use shell from within the makefile

There is a function called shell in makefiles which will
call a function in the shell. So this:

$(shell pwd)

will work within the makefile. However, it will not work on
the shell. So in the makefile you can use something like:

./configure --prefix="$(shell pwd)/../../local"

Use the abspath function in the makefile

There is also a function called abspath within make, which uses
an internal function (not the shell) to get an absolute path. You
can used this as something like:

$(abspath ../../local)

to get the path of a file. So the makefile command becomes:

./configure --prefix="$(abspath ../../local)"

[cianyleow]

@m8pple your help file on the slightly nicer version of the command has an extra ')' at the end before the double quotes.

[SzeKiatTan]

I used $(CURDIR) and it seems to work in the makefile. Just wondering if it is a legitimate usage?

[m8pple]

Yes, you're right CURDIR works too. In fact it's probably a
better solution than my suggestions when working in the
makefile. I'll note it in the main readme.