RFR: 8326583: Remove over-generalized DefineNativeToolchain solution [v3]

[Daniel Jeliński]

On Mon, 26 Feb 2024 20:21:55 GMT, Magnus Ihse Bursie <ihse at openjdk.org> wrote:

>> The idea of setting up general "toolchains" in the native build was good, but it turned out that we really only need a single toolchain, with a single twist: if it should use CC or CPP to link. This is better described by a specific argument to SetupNativeCompilation, LANG := C++ or LANG := C (the default).
>> 
>> There is a single exception to this rule, and that is if we want to compile for the build platform rather than the target platform. (This is only done for adlc) To keep expressing this difference, introduce TARGET_TYPE := BUILD (or TARGET_TYPE := TARGET, the default).
>> 
>> The final odd-case was the hack for building hsdis/bin on mingw. This can be resolved using direct variables to SetupNativeCompilation, instead of first creating a toolchain.
>> 
>> Doing this refactoring will simplify the SetupNativeCompilation code, and make it much clearer if we use the C or C++ linker.
>
> Magnus Ihse Bursie has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Rename LANG to LINK_TYPE

can we get rid of LDCXX? On my system LDCXX is mapped to `g++` and LD is `gcc`; I searched for the differences, and the only thing I could find is that `g++` implicitly adds `-lstdc++ -shared-libgcc`; I suppose we could explicitly add these options, and use gcc everywhere.

See:
https://stackoverflow.com/a/172592
https://gcc.gnu.org/onlinedocs/gcc/Link-Options.html

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PR Comment: https://git.openjdk.org/jdk/pull/17986#issuecomment-1965991536