Attempt to build MariaDB server on MacOS could result in
compilation errors like the following one:

  In file included from server-10.2/storage/perfschema/cursor_by_account.cc:28:
  In file included from server-10.2/include/my_global.h:287:
  In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX11.3.sdk/usr/include/c++/v1/math.h:309:
  In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX11.3.sdk/usr/include/c++/v1/type_traits:418:
    server-10.2/version:1:1: error: expected unqualified-id

    MYSQL_VERSION_MAJOR=10
    ^
  server-10.2/build.dir/include/my_config.h:529:29: note: expanded from macro 'MYSQL_VERSION_MAJOR'

This kind of compiler errors occur by the reson that compiler's system headers
contain the directive '#include <version>' and a compiler is invoked
with -I${CMAKE_SOURCE_DIR}.

The MariaDB source code root directory contains the file VERSION that is handled
by the compiler during processing the directive #include <version>
since file names on MacOS are case insensetive, so version and VERSION is treated as
the same file name.

To fix the issue the source code root directory should be removed from a list
of directories used by the compiler for include search path.