configure: error: The pkg-config script could not be found or is too old

Today while trying to install …Do not remember what software… in a new computer with Arch Linux on it, and after installed pkgtools I’ve found this error:

checking for pkg-config... no
checking for IFT... configure: error: The pkg-config script could not be found or is too old.  Make sure it
is in your PATH or set the PKG_CONFIG environment variable to the full
path to pkg-config.

So, the obvious solution is to install pkg-config, but that lead me to some minutes lost until I realized that was the problem.

Then, here it is, it may be useful for someone in the future.

pacman -Sy pkg-config

After that you should not have the problem again.

Conclusion

Sometimes the solution is just in front of your nose, but you just can’t find it.