[bug] NMake toolchain works with CLang-cl incorrectly

[molotok-sms]

Describe the bug

Hi! Thank you for your great project!

I faced with the following issue.

Context:

• Conan supports CLang-cl and knows how to set debug parameters for it (for example, gline-tables-only and fno-inline);
• Conan has NMakeToolchain and supports NMake;

Issue:

• Conan sets the generated CLang build_type_flags to the CL environment variable (it's okay because CLang-cl supports it) and does it in the MSVC CL compiler format (Conan tranforms - characters to /) and that is the problem.

I see some possible solutions:

1. Disable transformations in NMakeToolchain if the compiler is CLang-cl;
2. Follow the previous point and to add the filling of the CFLAGS environment variable instead of the CL one.

Thank you!

How to reproduce it

No response

[memsharded]

Hi @molotok-sms

Hi! Thank you for your great project!

Thanks for your kind words!

Thanks for your report too.

I think this was addressed in #17387, which was released in latest Conan 2.10.
The way it works is it uses the tools.build:compiler_executables information to see if it is using clang-cl or not, and avoid using the wrong flags.

Could you please try that? Thanks for your feedback!

[molotok-sms]

Thank you for the quick response!

I use the Conan version 2.10.0 from Pixi (Conda).
The mentioned changes are good but unfortunately it isn't enough.

In my case, "the right clang flags" pass through the NMakeToolchain "_format_options" function and become invalid.
It seems it would be good to improve the NMakeToolchain to support not only "msvc" compiler, but "clang-cl' too.

[molotok-sms]

I attached the log of errors when NMakeToolchain transformed the format of debug parameters: