Because you might not have a build script?

cortesoft 3 hours ago | parent | next [-]

Then how is anything ending up in the build directory?

drdec 4 hours ago | parent | prev [-]

Then why do you need a build directory?

	▲	himata4113 4 hours ago \| parent [-]
		qemu: mkdir build; cd build; ../configure, some projects are like that