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2020-04-29build system: remove KBUILD_STR()Jean-Philippe Brucker
When using GNU Make >=4.3, the KBUILD_STR() definition interferes badly with dependency checks during build, and forces a complete rebuild every time Make runs. In if_changed_rule, Kconfig checks if the command used to build a file has changed since last execution. The previous command is stored in the generated .<file>.o.cmd file. For example applets/.applets.o.cmd defines a "cmd_applets/applets.o" variable: cmd_applets/applets.o := gcc ... -D"KBUILD_STR(s)=#s" ... Here the '#' should be escaped with a backslash, otherwise GNU Make interprets it as starting a comment, and ignore the rest of the variable. As a result of this truncation, the previous command doesn't equal the new command and Make rebuilds each target. The problem started to appear when GNU Make 4.3 (released January 2020), introduced a backward-incompatible fix to macros containing a '#'. While the above use of '#', a simple Make variable, still needs to be escaped, a '#' within a function invocation doesn't need to be escaped anymore. As Martin Dorey explained on the GNU Make discussion [1], the above declaration is generated from make-cmd, defined as: make-cmd = $(subst \#,\\\#,$(subst $$,$$$$,$(call escsq,$(cmd_$(1)))) Since GNU Make 4.3, the first argument of subst should not have a backslash. make-cmd now looks for literally \# and doesn't find it, and as a result doesn't add the backslash when generating .o.cmd files. [1] http://savannah.gnu.org/bugs/?20513 We could fix it by changing make-cmd to "$(subst #,\#,...)", but to avoid compatibility headaches, simply get rid of the KBUILD_STR definition, as done in Linux by b42841b7bb62 ("kbuild: Get rid of KBUILD_STR"). Quote the string arguments directly rather than asking the preprocessor to quote them. Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2010-07-26*: trailing empty lines removedDenys Vlasenko
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2008-11-08build system: remove '-Wl,' when we pass flags to ld.Denis Vlasenko
2008-06-06Build system: track -Wl,-elf2flt in CFLAGS_busybox too.Denis Vlasenko
Document in comments that it generally should be thers, not in LDFLAGS
2007-01-11Trailing whitespace removal over entire treeDenis Vlasenko
2006-10-05build system overhaulDenis Vlasenko