• Masahiro Yamada's avatar
    kbuild: simplify silent build (-s) detection · 6f0fa58e
    Masahiro Yamada authored
    This allows to detect -s (--silent) option without checking GNU Make
    version.
    
    As commit e36aaea2 ("kbuild: Fix silent builds with make-4")
    pointed out, GNU Make 4.x changed the way/order it presents the
    command line options into MAKEFLAGS.
    
    In Make 3.8x, 's' is always the first in a group of short options.
    The group may be prefixed with '-' in some cases.
    
    In Make 4.x, 's' is always the last in a group of short options.
    
    As commit e6ac89fa ("kbuild: Correctly deal with make options
    which contain an 's'") addressed, we also need to deal with long
    options that contain 's', like --warn-undefined-variables.
    
    Test cases:
    
    [1] command line input:    make --silent
         -> MAKEFLAGS for Make 3.8x:    s
         -> MAKEFLAGS for Make 4.x :    s
    
    [2] command line input:    make -srR
         -> MAKEFLAGS for Make 3.8x:    sRr
         -> MAKEFLAGS for Make 4.x :    rRs
    
    [3] command line input:    make -s -rR --warn-undefined-variables
         -> MAKEFLAGS for Make 3.8x:    --warn-undefined-variables -sRr
         -> MAKEFLAGS for Make 4.x :    rRs --warn-undefined-variables
    
    My idea to cater to all the cases more easily is to filter out long
    options (--%), then search 's' with $(findstring ...).  This way will
    be more future-proof even if future versions of Make put 's' in the
    middle of the group.
    Signed-off-by: default avatarMasahiro Yamada <yamada.masahiro@socionext.com>
    6f0fa58e
Makefile 58.5 KB