commit 54ba6c27b504f43b59b0d91da0165995c66d9a3d
author Sergey Sharybin <sergey.vfx@gmail.com> Sat Dec 23 18:18:24 2017 +0100
committer Sergey Sharybin <sergey.vfx@gmail.com> Tue Apr 23 12:16:28 2019 +0200
tree ee038d7fec6688a9310ff10c70a61755421e8254
parent fac46d50eb50d7c0830f673cadc36e63407e40bf

Fix missing declaration warnings in Ceres code

This commit includes the following:

- Changes to CMake to make it safer to see which compiler flags are supported,
  so this way we do not need to worry about version checks in CMake.

- Unix platforms (which includes both Linux and Apple as far as i can tell)
  will now enable -Wmissing-declarations warning for the whole Ceres.

- Changes in all sources to solve missing declaration warning. In most cases
  it was either matter of using static qualifier or moving functions to an
  anonymous namespace.

  In one case the function got removed, since it seems to be unused.

  Additionally, in slam examples there was a non-inlined function implementation
  in a header, which is a direct way to cause linking errors if other .cc file
  will include that helper header.

- All third party sources (which is currently only gmock) has this extra
  paranoid warning disabled.

This warning is important in the following cases:

- Detect helper functions which are not needed anymore.
- Avoid unnoticed pollution of namespace.
- Avoid bad level calls.
- Avoid missing updates in header files after changes in implementation file.
- Helps integrating Ceres into software where paranoid warnings are important.

Change-Id: I9b1044aced3910d8c6b2356cfe2bf57f3c8c58db