Make error: missing separator

Question

I am getting the following error running make:

Makefile:168: *** missing separator.  Stop.

What is causing this?

Answer 1

As indicated in the online manual, the most common cause for that error is that lines are indented with spaces when make expects tab characters.

Correct

target: 
\tcmd

where \t is TAB (U+0009)

Wrong

target:
....cmd

where each . represents a SPACE (U+0020).