For each CONFIG_SYMBOL, include/bb_config.h now has both ENABLE_SYMBOL
and USE_SYMBOL(x). ENABLE_SYMBOL is still always defined (1 or 0) so that
if(ENABLE) should optimize out when it's zero. The USE_SYMBOL(X) will only
splice in X if the symbol is defined, otherwise it'll be empty.
Thus we can convert this:
#ifdef CONFIG_ARGS
opt = bb_getopt_ulflags(argc, argv, "ab:c"
#ifdef CONFIG_THINGY
"d:"
#endif
, &bvalue
#ifdef CONFIG_THINGY
, &thingy
#endif
);
#endif
into this:
if (ENABLE_ARGS) {
opt = bb_getopt_ulflags(argc, argv, "ab:c" USE_THINGY("d:"), &bvalue
USE_THINGY(, &thingy));
}
And it should produce the same code.
Unlike the old versions in include/_usage.h, the new USE_SYMBOL(x) can handle
commas in its arguments (as shown above). (The _usage.h file is obsolete and
no longer generated.)
Nobody should need to include config.h directly anymore, bb_config.h should
define all the configuration stuff we need. Someday, the CONFIG_SYMBOL
versions should go away in favor of ENABLE_SYMBOL and USE_SYMBOL().
Thanks to vodz for the new version of bb_mkdep.c that works with function
macros.
