Ёбаный make 4.3 и его авторы с автолулзами головного мозга: * WARNING: Backward-incompatibility! Number signs (#) appearing inside a macro reference or function invocation no longer introduce comments and should not be escaped with backslashes: thus a call such as: foo := $(shell echo '#') is legal. Previously the number sign needed to be escaped, for example: foo := $(shell echo '\#') Now this latter will resolve to "\#". If you want to write makefiles portable to both versions, assign the number sign to a variable: H := \# foo := $(shell echo '$H') This was claimed to be fixed in 3.81, but wasn't, for some reason. To detect this change search for 'nocomment' in the .FEATURES variable.