Type: LanguageService

• OS and Version: Windows 10 / 10.0.17134
• VS Code Version: 1.29.1 (user setup)
• C/C++ Extension Version: 0.20.1
• Other extensions you installed (and if the issue persists after disabling them): The other extensions are not related with C/C++ extension

Problem: I have clearly installed Windows 10 to my computer and then I have installed Ubuntu (18.04) WSL application and I installed gcc-4.8 to my Ubuntu WSL. I haven't installed any other compiler or something like that. Then I want to use this gcc-4.8 installation which is on Ubuntu, to enable Intellisense feature of extension. I found a documentation link: "https://github.com/Microsoft/vscode-cpptools/blob/master/Documentation/LanguageServer/Windows%20Subsystem%20for%20Linux.md". I applied these steps for a folder specific settings and it works clearly. Then, I want to set this gcc-4.8 Intellisense settings as default. So, I want to Intellisense works even if I didn't open a folder, only opened a C++ file. For this case, I edited C/C++ extension settings from settings and set default compiler path to "/usr/bin/gcc". When I have saved and restarted VSCode, the output of extension shows an error:
"
Attempting to get defaults from compiler found on the machine: ' '
Attempting to get defaults from compiler found on the machine: /usr/bin/gcc
Failed to spawn process. Error: 2 (The system cannot find the file specified.)
cpptools/activeDocumentChange
cpptools/textEditorSelectionChange
cpptools/didChangeFolderSettings
Attempting to get defaults from compiler in "compilerPath" property: '/usr/bin/gcc'
Failed to spawn process. Error: 2 (The system cannot find the file specified.)
Code browsing service initialized
Attempting to get defaults from compiler in "compilerPath" property: '/usr/bin/gcc'
Failed to spawn process. Error: 2 (The system cannot find the file specified.)
"

So, it gives this error and Intellisense is not working correctly. It gives an error for stdlib.h library include. I tried a lot of things to solve this problem but none of them has worked.

Here is a part of my settings.json:
"
"C_Cpp.intelliSenseEngineFallback": "Disabled",
"C_Cpp.default.cStandard": "c11",
"C_Cpp.default.cppStandard": "c++17",
"C_Cpp.loggingLevel": "Debug",
"C_Cpp.default.windowsSdkVersion": "10.0.17134.0",
"