type safe option value getters

[dcbaker]

This adds a couple of methods to the OptionStore to work with options value in a type safe manner. This works by putting the type in the getter itself, this avoids the need for the pattern of:

opt = optstore.get_value_for('b_foo')
assert isinstance(opt, str), 'for mypy'

While also giving better error messages. Additionally, I've added a default= parameter, to allow not erroring when an options isn't available (a per-platform or per-compiler option). The end result is the following:

• get_value_for a type safe getter for a system value
• get_value_for_untyped a type unsafe getter for system values, works like get_value_for in current main
• get_value_for_target a type safe getter for an option that could be overwritten by a target
• get_value_for_target_untyped a type unsafe getter for an option that could be overwritten by a target, same as get_value_for_target in current main branch
• get_value_for_maybe_target a type safe getter that allows a target to be optional. This is a bit ugly, but I don't see a better way to handle this without duplicating code in a way that would lead to bugs.

this allows the following patterns to be eliminated:

opt = optstore.get_value_for_untyped(OptionKey('b_foo'))
assert isinstance(opt, str), 'for mypy'

with

opt = opstore.get_value_for(OptionKey('b_foo'), str)

(and the same for targets)

and

key = OptionKey('b_foo')
if target is not None:
    opt = opstore.get_value_for_target(target, key, str)
else:
    opt = opstore.get_value_for(key, str)

with

opt = optstore.get_value_for_maybe_target(target, OptionKey('b_foo'), str)

and

try:
    opt = opstore.get_value_for(OptionKey('b_foo'), bool)
except KeyError:
    opt = False

with

opt = optstore.get_value_for(OptionKey('b_foo'), bool, default=False)

This has been set to draft as I'm sure there will be some issues with Windows and the VS backend that need to be resolved.

[dcbaker]

There's a bug in "compilers: Fix the signature of get_option_{std,compile,link}_args", but I can't find it immediately by inspection

[bonzini]

I think this needs to be target if target is not None else subproject.

[bonzini]

The failing test logs (test cases\windows\14 resources with custom target depend_files):

[1/4] "C:\hostedtoolcache\windows\Python\3.10.11\x64\python.exe" "D:\a\1\s\test cases\windows\14 resources with custom target depend_files\ico\gen-ico.py" "../test cases/windows/14 resources with custom target depend_files/ico/sample.ico.in" "ico/sample.ico"
[2/4] "cl" "-Iprog.exe.p" "-I." "-I..\test cases\windows\14 resources with custom target depend_files" "-Ires" "/MDd" "/nologo" "/showIncludes" "/utf-8" "/W2" "/Od" "/Z7" "/Fdprog.exe.p\prog.c.pdb" /Foprog.exe.p/prog.c.obj "/c" "../test cases/windows/14 resources with custom target depend_files/prog.c"
[3/4] "C:\hostedtoolcache\windows\Python\3.10.11\x64\python.exe" "D:/a/1/s/meson.py" "--internal" "rc" "--rc" "C:/Program Files (x86)/Windows Kits/10/bin/10.0.26100.0//x64/rc.exe" "--cl" "cl" "--Xarg=/showIncludes" "--Xarg=/EP" "--Xarg=/nologo" "--Xarg=/DRC_INVOKED" "--Xarg=/Tc../test cases/windows/14 resources with custom target depend_files/res/myres.rc" "-ID:/a/1/s/b 3d59bc125c/ico" "/nologo" "/fores/res_myres.rc_myres.res" "../test cases/windows/14 resources with custom target depend_files/res/myres.rc"
myres.rc
myres.rc
[4/4] "link"  /MACHINE:x64 /OUT:prog.exe res/res_myres.rc_myres.res prog.exe.p/prog.c.obj "/release" "/nologo" "/DEBUG" "/PDB:prog.pdb" "/SUBSYSTEM:WINDOWS"
FAILED: prog.exe prog.pdb 
"link"  /MACHINE:x64 /OUT:prog.exe res/res_myres.rc_myres.res prog.exe.p/prog.c.obj "/release" "/nologo" "/DEBUG" "/PDB:prog.pdb" "/SUBSYSTEM:WINDOWS"
prog.c.obj : error LNK2019: unresolved external symbol __imp_LoadIconA referenced in function WinMain