This reverts commit 3a97fbd0.

This reverts commit 6b758edb.

This patch fixes the iterator incrementation.

Interpreters/Compiler.cpp contained hard-coded paths for system's
includes needed for query compiler. These paths were not portable
between different Linux distros and gcc/clang versions. For example,
Debian/Ubuntu use /usr/lib/gcc/x86_64-linux-gnu/*/include,
RHEL/Fedora use /usr/lib/gcc/x86_64-redhat-linux/*/include,
others use /usr/lib/gcc/*/include (without x86_64-XXX triplet).

Patch 68850012 "Embedded compiler fixes" attempted to fix this problem
by adding CMAKE_LIBRARY_ARCHITECTURE after /usr/lib. Unfortunally,
CMAKE_LIBRARY_ARCHITECTURE is not defined on RHEL/Fedora because someone
decided to omit "-gnu" from x86_64-redhat-linux (see RHBZ#1531678).

Patch 70e35d0b "Build fixes (#1718)" added a workaround for
undefined CMAKE_LIBRARY_ARCHITECTURE on RHEL/Fedora, but hasn't fixed
problem with missing /usr/lib/gcc/x86_64-redhat-linux/*/include/
in the list of hardcoded paths.

Remove hard-coded paths and get the list of `-isystem` includes directly
from bundled clickhouse-clang.

Other changes:

- Enable RPATH for the build directory to get working binaries
  without installing them by `make install`.

Allow to use system libgtest-dev/gtest-devel when -DUNBUNDLED is ON.

* Embedded compiler fixes

* common lib not needed for clang and lld

* Fix pthread link

* Fix shared build

* Arm fixes 1

* arm fix

* Unused fix

* Build fixes

* release --pbuilder

* release pbuilder fix

* FORCE_PBUILDER_CREATE=1 release

* release: Auto use clang with sanitizers

* Fix build without poco data odbc lib. zlib arm build fix.

* Fix freebsd build and build without mysql

* Tests: Dont eat my cpu!

* Test me

* Add link to Beijing meetup

* ignore presentations

* introduce requirements.txt

* Apply hacks by bayonet@ using monkey patching

* Simplify and fix patching of "single" docs on Mac OS (it still has a bug on chunk borders though)

Switching into markdown.

Edit page link is fixed too for both language versions of documentation.