"make dep" fails: missing separator

[scream314]

Running make dep on the repo cloned from Github fails:

make[2]: Entering directory '/root/pjproject/pjsip/build'
.pjsua2-lib-armv7l-unknown-linux-gnueabihf.depend:1: *** missing separator (did you mean TAB instead of 8 spaces?).  Stop.
make[2]: Leaving directory '/root/pjproject/pjsip/build'
Makefile:317: recipe for target 'depend' failed
make[1]: *** [depend] Error 2
make[1]: Leaving directory '/root/pjproject/pjsip/build'
Makefile:14: recipe for target 'dep' failed
make: *** [dep] Error 1

Tried to make sure no beginning of any line in the Makefile contains any other whitespace than TAB, but the error still appears.