# git gc
# git rev-parse -q --verify c7c90e121e992eefdf07945e5a6e9cf097b29463^{commit}
# git fetch -q -n -f git://gitlab.ozlabs.ibm.com/mirror/linux-kbuild.git for-next
# git rev-parse -q --verify c7c90e121e992eefdf07945e5a6e9cf097b29463^{commit}
c7c90e121e992eefdf07945e5a6e9cf097b29463
# git checkout -q -f -B kisskb c7c90e121e992eefdf07945e5a6e9cf097b29463
# git clean -qxdf
# < git log -1
# commit c7c90e121e992eefdf07945e5a6e9cf097b29463
# Author: Bjorn Helgaas <bhelgaas@google.com>
# Date:   Tue Jun 1 16:31:43 2021 -0500
# 
#     kconfig.h: explain IS_MODULE(), IS_ENABLED()
#     
#     Extend IS_MODULE() and IS_ENABLED comments to explain why one might use
#     "#if IS_ENABLED(CONFIG_FOO)" instead of "#ifdef CONFIG_FOO".
#     
#     To wit, "#ifdef CONFIG_FOO" is true only for CONFIG_FOO=y, while
#     "#if IS_ENABLED(CONFIG_FOO)" is true for both CONFIG_FOO=y and
#     CONFIG_FOO=m.
#     
#     This is because "CONFIG_FOO=m" in .config does not result in "CONFIG_FOO"
#     being defined.  The actual definitions are in autoconf.h, where:
#     
#       CONFIG_FOO=y   results in   #define CONFIG_FOO 1
#       CONFIG_FOO=m   results in   #define CONFIG_FOO_MODULE 1
#     
#     Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
#     Acked-by: Randy Dunlap <rdunlap@infradead.org>
#     Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
# < /opt/cross/kisskb/korg/gcc-4.9.4-nolibc/x86_64-linux/bin/x86_64-linux-gcc --version
# < /opt/cross/kisskb/korg/gcc-4.9.4-nolibc/x86_64-linux/bin/x86_64-linux-ld --version
# < git log --format=%s --max-count=1 c7c90e121e992eefdf07945e5a6e9cf097b29463
# < make -s -j 48 ARCH=x86_64 O=/kisskb/build/kbuild_x86_64-allnoconfig_x86_64-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/x86_64-linux/bin/x86_64-linux-  allnoconfig
# < make -s -j 48 ARCH=x86_64 O=/kisskb/build/kbuild_x86_64-allnoconfig_x86_64-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/x86_64-linux/bin/x86_64-linux-  help
# make -s -j 48 ARCH=x86_64 O=/kisskb/build/kbuild_x86_64-allnoconfig_x86_64-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/x86_64-linux/bin/x86_64-linux-  olddefconfig
# make -s -j 48 ARCH=x86_64 O=/kisskb/build/kbuild_x86_64-allnoconfig_x86_64-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/x86_64-linux/bin/x86_64-linux-  
Completed OK
# rm -rf /kisskb/build/kbuild_x86_64-allnoconfig_x86_64-gcc4.9
# Build took: 0:04:39.567433