This does two things:
* On windows GCC-like compilers, the subsystem is always explicitly
specified (either -mwindows or -mconsole). MSVC is already explicit.
* The gui_app linker flags are now added after those mandated by
external dependencies. This is because some misguided libraries (such
as SDL) think that hijacking `main()` and forcing `-mwindows` in link
flags is clever. We must unconditionally override such misuses to let
gui_app work as intended.
Also adds test case for shared library linking.
Closes#4912, at least on Linux. The future 0.50.0 does not yet claim to
support CUDA on systems other than Linux and backends other than Ninja.
Instead use coredata.compiler_options.<machine>. This brings the cross
and native code paths closer together, since both now use that.
Command line options are interpreted just as before, for backwards
compatibility. This does introduce some funny conditionals. In the
future, I'd like to change the interpretation of command line options so
- The logic is cross-agnostic, i.e. there are no conditions affected by
`is_cross_build()`.
- Compiler args for both the build and host machines can always be
controlled by the command line.
- Compiler args for both machines can always be controlled separately.
macOS provides the tool `lipo` to check the archs supported by an
object (executable, static library, dylib, etc). This is especially
useful for fat archives, but it also helps with thin archives.
Without this, the linker will fail to link to the library we mistakenly
'found' like so:
ld: warning: ignoring file /path/to/libfoo.a, missing required architecture armv7 in file /path/to/libfoo.a
Instead of only doing a naive filesystem search, also run the linker
so that it can tell us whether the -F path specified actually contains
the framework we're looking for.
Unfortunately, `extraframework` searching is still not 100% correct in
the case when since we want to search in either /Library/Frameworks or
in /System/Library/Frameworks but not in both. The -Z flag disables
searching in those prefixes and would in theory allow this, but then
you cannot force the linker to look in those by manually adding -F
args, so that doesn't work.
It appears that LIB/LINK default to the host architecture if they can't
guess it from the first object. With the MSVC toolchain, resource files
are (usually) compiled to an arch-neutral .res format. Always
explicitly provide a '/MACHINE:' argument to avoid it guessing
incorrectly when cross-compiling.
Store the MSVC compiler target architecture ('x86', 'x64' or 'ARM' (this
is ARM64, I believe)), rather than just if it's x64 or not.
The regex used for target architecture should be ok, based on this list
of [1] version outputs, but we assume x86 if no match, for safety's
sake.
[1] https://stackoverflow.com/a/1233332/1951600
Also detect arch even if cl outputs version to stdout.
Ditto for clang-cl
Future work: is_64 is now only used in get_instruction_set_args()