Help: Fix typo in cmake-qt manual.

Do -> To.
Merge branch 'fix-Qt-manual-typo' into release
create_test_sourcelist: Initialize variable at declaration

Clang -Wconditional-uninitialized warns otherwise.
Policies: omit warnings about unset policies when they are actually set to NEW
Merge branch 'clang-warnings' into release
Merge branch 'fix_policy_diagnostics' into release
Help: Revise and format policy CMP0025 and CMP0047 docs

Add inline reST markup as appropriate.  Word CMP0047 docs more like
those of CMP0025.  State explicitly that the policies must be set
before the project or enable_language command calls.
Do not warn by default when policy CMP0025 or CMP0047 is not set

These policies are triggered by the use of a particular compiler rather
than outdated CMake code in a project.  Avoid warning in every project
that enables a language by not displaying the policy warning by default.
Add variable CMAKE_POLICY_WARNING_CMP<NNNN> to control the warning
explicitly; otherwise enable the warning with --debug-output or --trace.

This breaks with strict policy convention because it does not provide
developers with any warning about the behavior change by default.
Existing projects will continue to build without a warning or change in
behavior.  When a developer changes the minimum required version of
CMake in a project to a sufficiently high value (3.0), the project will
suddenly get the new compiler id and may break, but at least the
breakage comes with a change to the project rather than the version of
CMake used to build it.

Breaking strict policy convention is worthwhile in this case because
very few projects will be affected by the behavior change but every
project would have to see the warning if it were enabled by default.
Merge branch 'revise-compiler-id-policies' into release
Qt4Macros: Make QT4_CREATE_MOC_COMMAND a function

QT4_CREATE_MOC_COMMAND is given a moc_flags argument that contains the
COMPILE_DEFINITIONS and a potentially large list of include directories.
Since it is a macro, the ${moc_flags} reference is replaced with this
content and sent through cmMakefile::ExpandVariablesInString (EVIS).
Since commit v3.0.0-rc1~138^2 (Qt4: Use generator expression in
COMPILE_DEFINITIONS, 2014-01-13) the COMPILE_DEFINITIONS value contains
a '$' so the EVIS fast-path is no longer used.  Instead the full
cmCommandArgumentParserHelper is now used on the large input, which is
very slow (since it was originally created for hand-written code).

Change QT4_CREATE_MOC_COMMAND to a function instead of a macro to avoid
passing large content through EVIS.  This makes it significantly faster.
Merge branch 'Qt4Macros-moc-performance' into release