The -Qunused-arguments flag disables the warning where some flags are
not relevant to a compilation. This commonly happens when compiling
assembly files (.s or .S files) because some flags are specific to C and
not relevant to assembly.
Because practically all baremetal targets need some form of assembly,
this flag is added to most CFlags. This creates a lot of noise. And it
is also added for compiling C code where it might hide bugs (by hiding
the fact a flag is actually unused).
This commit adds the flag to all assembly compilations and removes them
from all target JSON files.
This patch adds support for passing CFLAGS added in #cgo lines of the
CGo preprocessing phase to the compiler when compiling C files inside
packages. This is expected and convenient but didn't work before.
This probably won't speed up the build on multicore systems (the build
is still dominated by the whole-program optimization step) but should be
useful at a later date for other optimizations. For example, I intend to
eventually optimize each package individually including C files, which
should enable cross-language optimizations (inlining C functions into Go
functions, for example). For that to work, accurate dependency tracking
is important.
