Add settings options to conanfile.

[ngrodzitski]

Settings will be removed from package_id after calling self.info.header_only(), but they a helpfull for Conan CMake helper to detect generator correctly.

[ngrodzitski]

Without this the following issue arises on windows having VS2017/VS2019 installed.

conan install -s compiler="Visual Studio" -s compiler.version=15 -s build_type=Release -s compiler.runtime=MD optional-lite/3.2.0@nonstd-lite/stable

With output:

optional-lite/3.2.0@nonstd-lite/stable: Building package from source as defined by build_policy='missing'

Installing package: optional-lite/3.2.0@nonstd-lite/stable

Requirements

   optional-lite/3.2.0@nonstd-lite/stable from 'nonstd-lite' - Cache

Packages

   optional-lite/3.2.0@nonstd-lite/stable:5ab84d6acfe1f23c4fae0ab88f26e3a396351ac9 - Build



optional-lite/3.2.0@nonstd-lite/stable: Building your package in D:\conan_local\data\optional-lite\3.2.0\nonstd-lite\stable\build\5ab84d6acf

e1f23c4fae0ab88f26e3a396351ac9

optional-lite/3.2.0@nonstd-lite/stable: Copying sources to build folder

optional-lite/3.2.0@nonstd-lite/stable: Generator txt created conanbuildinfo.txt

optional-lite/3.2.0@nonstd-lite/stable: Calling build()

optional-lite/3.2.0@nonstd-lite/stable: Package '5ab84d6acfe1f23c4fae0ab88f26e3a396351ac9' built

optional-lite/3.2.0@nonstd-lite/stable: Build folder D:\conan_local\data\optional-lite\3.2.0\nonstd-lite\stable\build\5ab84d6acfe1f23c4fae0a

b88f26e3a396351ac9

optional-lite/3.2.0@nonstd-lite/stable: Generated conaninfo.txt

optional-lite/3.2.0@nonstd-lite/stable: Generated conanbuildinfo.txt

optional-lite/3.2.0@nonstd-lite/stable: Generating the package

optional-lite/3.2.0@nonstd-lite/stable: Package folder D:\conan_local\data\optional-lite\3.2.0\nonstd-lite\stable\package\5ab84d6acfe1f23c4f

ae0ab88f26e3a396351ac9

optional-lite/3.2.0@nonstd-lite/stable: Calling package()

optional-lite/3.2.0@nonstd-lite/stable: WARN: CMake generator could not be deduced from settings!!!!

-- Building for: Visual Studio 16 2019

-- Selecting Windows SDK version 8.1 to target Windows 6.1.7601.

-- The CXX compiler identification is unknown

CMake Error at CMakeLists.txt:12 (project):

 No CMAKE_CXX_COMPILER could be found.







-- Configuring incomplete, errors occurred!

See also "D:/conan_local/data/optional-lite/3.2.0/nonstd-lite/stable/build/5ab84d6acfe1f23c4fae0ab88f26e3a396351ac9/CMakeFiles/CMakeOutput.l

og".

See also "D:/conan_local/data/optional-lite/3.2.0/nonstd-lite/stable/build/5ab84d6acfe1f23c4fae0ab88f26e3a396351ac9/CMakeFiles/CMakeError.lo

g".

ERROR: optional-lite/3.2.0@nonstd-lite/stable: Error in package() method, line 22

       cmake.configure()

       ConanException: Error 1 while executing cd D:\conan_local\data\optional-lite\3.2.0\nonstd-lite\stable\build\5ab84d6acfe1f23c4fae0ab8

8f26e3a396351ac9 && cmake -DCONAN_EXPORTED="1" -DCONAN_IN_LOCAL_CACHE="ON" -DCMAKE_INSTALL_PREFIX="D:\conan_local\data\optional-lite\3.2.0\n

onstd-lite\stable\package\5ab84d6acfe1f23c4fae0ab88f26e3a396351ac9" -DCMAKE_INSTALL_BINDIR="bin" -DCMAKE_INSTALL_SBINDIR="bin" -DCMAKE_INSTA

LL_LIBEXECDIR="bin" -DCMAKE_INSTALL_LIBDIR="lib" -DCMAKE_INSTALL_INCLUDEDIR="include" -DCMAKE_INSTALL_OLDINCLUDEDIR="include" -DCMAKE_INSTAL

L_DATAROOTDIR="share" -DCMAKE_EXPORT_NO_PACKAGE_REGISTRY="ON" -DOPTIONAL_LITE_OPT_BUILD_TESTS="OFF" -DOPTIONAL_LITE_OPT_BUILD_EXAMPLES="OFF"

-Wno-dev D:\conan_local\data\optional-lite\3.2.0\nonstd-lite\stable\build\5ab84d6acfe1f23c4fae0ab88f26e3a396351ac9

The issue goes from this:

optional-lite/3.2.0@nonstd-lite/stable: WARN: CMake generator could not be deduced from settings
-- Building for: Visual Studio 16 2019

Conan CMake helper doesn't know the compiler so tries to determine generator itself and picks up the latest it can find which stands for Visual Studio 16 2019 presented in the system.

Those settings are harmless, because self.info.header_only() removes them from package_id.