Bottom line: If we want to reduce D's binary size there are two pieces
of low-hanging fruit:
1. Make -L--gc-sections the default in dmd.conf on Linux and probably
other Posix OS's.
2. Add -ffunction-sections and -fdata-sections or equivalents to DMD
and compile Phobos with these enabled. I have no idea how hard this
would be, but I imagine it would be easy for someone who's already
familiar with object file formats.
Seems like --gc-sections _can_ have its pitfalls:
http://blog.flameeyes.eu/2009/11/21/garbage-collecting-sections-is-not-for-production
Also I read somewhere that --gc-sections isn't always supported (no
standard switch or something like that).
I personally see no reason not to use -ffunction-sections and
-fdata-sections for compiling phobos though, cause a test with gdc didn't
even result in a much bigger lib file, nor did it take significantly
longer to compile/link.
That site I linked claims though, that it does mean serious overhead even
if --gc-sections is omitted then.
So we have to do tests with huge codebases first.
