Merging r367115, r367125, r367127, and r367153.

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r367115 | jdevlieghere | 2019-07-26 16:26:33 +0200 (Fri, 26 Jul 2019) | 6 lines

[CMake] Loosen Python version check and ignore patch version

Some versions of macOS report a different patch version for the system
provided interpreter and libraries.

Differential revision: https://reviews.llvm.org/D65230
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r367125 | jdevlieghere | 2019-07-26 18:15:19 +0200 (Fri, 26 Jul 2019) | 3 lines

[CMake] Print Python version on Windows

Trying to figure out what's causing the Windows bot to fail.
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r367127 | jdevlieghere | 2019-07-26 18:32:49 +0200 (Fri, 26 Jul 2019) | 4 lines

[CMake] Fix find_python_libs_windows

Exporting PYTHON_INCLUDE_DIR to the Python scope somehow got lost in my
last change. Add it back again. This should fix the Windows bot!
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r367153 | jdevlieghere | 2019-07-26 22:58:10 +0200 (Fri, 26 Jul 2019) | 5 lines

[CMake] Print the correct variables

This didn't get updated after we decided to set PYTHON_MAJOR_VERSION and
PYTHON_MINOR_VERSION in find_python_libs_windows, instead of parsing the
variables ourselves.
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llvm-svn: 369903