Revert "fix: use both absolute and relative header paths in header matching (#362)"

[danmar]

This reverts commit c4b6e37.

There was build errors when simplecpp was used in cppcheck:

       "D:\a\cppcheck\cppcheck\cppcheck.sln" (default target) (1) ->
       "D:\a\cppcheck\cppcheck\cli\cli.vcxproj.metaproj" (default target) (2) ->
       "D:\a\cppcheck\cppcheck\lib\cppcheck.vcxproj" (default target) (4) ->
       (ClCompile target) -> 
         D:\a\cppcheck\cppcheck\externals\simplecpp\simplecpp.cpp(152,13): error C2375: 'startsWith': redefinition; different linkage [D:\a\cppcheck\cppcheck\lib\cppcheck.vcxproj]
         D:\a\cppcheck\cppcheck\externals\simplecpp\simplecpp.cpp(2726,17): error C2440: 'return': cannot convert from 'TCHAR [260]' to 'std::basic_string<char,std::char_traits<char>,std::allocator<char>>' [D:\a\cppcheck\cppcheck\lib\cppcheck.vcxproj]
         D:\a\cppcheck\cppcheck\externals\simplecpp\simplecpp.cpp(2753,8): error C2264: 'startsWith': error in function definition or declaration; function not called [D:\a\cppcheck\cppcheck\lib\cppcheck.vcxproj]

[danmar]

@Tal500 This reverts your fix. Please feel free to revert this and look at the error messages. Ideally we should be able to reproduce them here in the simplecpp repo also.

[firewave]

We should be able to detect this earlier - I filed #417 about that.

[Tal500]

@Tal500 This reverts your fix. Please feel free to revert this and look at the error messages. Ideally we should be able to reproduce them here in the simplecpp repo also.

I think I fixed these issues by #418.
Please tell me if there are any Windows build issue that are left (my Windows resources are limited, but I tried my best).