What is wrong with makefile?

Question

I'm trying to compile kernel of android, then get error.

/home/igor/work/hwp6s-kernel/arch/arm/mach-hi6620/pwrctrl/Makefile:9: *** missing separator.  Stop.
      File makefile
EXTRA_CFLAGS   +=   -wformat

obj-y               += common/
obj-y               += dfsMgr/
obj-y               += periMgr/
obj-y               += sleepMgr/
obj-y               += hotplug/
obj-y               += test/
EXTRA_CFLAGS -= -Wformat

Answer 1

There is no -= operator in makefiles. Make is getting confused when reading this.

Even if that operator did exist (or you correctly used $(filter-out ...)), you would not get your desired effect. The obj-y is simply adding things to a list, which is processed after the kbuild makefile is read. At that time, the EXTRA_CFLAGS value which existed at the end of reading the kbuild makefile would take effect.