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  • Masahiro Yamada's avatar
    Makefile: prepare for using Kbuild-style Makefile · ce28d7ac
    Masahiro Yamada authored and Tom Rini's avatar Tom Rini committed
    
    
    Every makefile in sub directories has common lines
    at the top and the bottom.
    This commit pushes the common parts into script/Makefile.build.
    
    Going forward sub-makefiles only need to describe this part:
    
        COBJS := ...
        COBJS += ...
        SOBJS := ...
    
    But using obj-y is preferable to prepare for switching to Kbuild.
    
    The conventional (non-Kbuild) Makefile style is still supported.
    This is achieved by greping the Makefile before entering into it.
    U-Boot conventional sub makefiles always include some other makefiles.
    So the build system searches a line beginning with "include" keyword
    in the makefile in order to distinguish which style it is.
    If the Makefile include a "include" line, we assume it is a conventional
    U-Boot style. Otherwise, it is treated as a Kbuild-style makefile.
    
    With this tweak, we can switch sub-makefiles
    from U-Boot style to Kbuild style little by little.
    
    obj-y := foo/
    syntax (descending into the sub directory) is not supportd yet.
    It will be implemented in the upcomming commit.
    
    Signed-off-by: default avatarMasahiro Yamada <yamada.m@jp.panasonic.com>
    Cc: Simon Glass <sjg@chromium.org>
    Cc: Tom Rini <trini@ti.com>
    ce28d7ac