ClearMatches: Only clear matches which were actually set

ClearMatches was clearing many variables which were never set in the
first place. Instead, store how many matches were made last time and
only clear those. It is moved to the cmMakefile class since it is a
common utility used by multiple commands.
ClearMatches: Store match variable names statically

Constructing the names and then turning them into a std::string is
non-negligible in performance testing.
StoreMatches: Minor cleanups
Merge branch 'ExternalProject-verify-cmake-var' into release
CMake Nightly Date Stamp
Tests: Fix Qt4Targets test inner project name

The try_compile command third argument must be the value given to
the project() command in the IncrmentalMoc/CMakeLists.txt file.
While at it, extend the error message to include the try_compile
output to make debugging easier.
Merge topic 'dont-rewrite-moc-parameter-file' into next

1dda0f47 Tests: Fix Qt4Targets test inner project name
Help: Add notes for topic 'FindCUDA-cubin-fatbin'
Merge topic 'FindCUDA-cubin-fatbin' into next

80209fdb Help: Add notes for topic 'FindCUDA-cubin-fatbin'
Merge topic 'drop-release-on-ferrari'

c962c21c Utilities/Release: Drop IRIX binary generation on ferrari
Merge topic 'ExternalProject-verify-cmake-var'

420280f3 ExternalProject: Fix path to cmake in verify script
Merge topic 'FindCUDA-cubin-fatbin'

80209fdb Help: Add notes for topic 'FindCUDA-cubin-fatbin'
231b30db FindCUDA: Add support for compilation to fatbin & cubin modules
Merge topic 'file-generate-if-different'

42e1cd13 file(GENERATE): Only write the file if content is different.
Merge branch 'master' into next
Help: Add notes for topic 'ExternalData-missing-not-fatal'
Merge topic 'ExternalData-missing-not-fatal' into next

4a5cf964 Help: Add notes for topic 'ExternalData-missing-not-fatal'
Help: Add notes for topic 'UseSWIG-guess_module_name'
Merge topic 'UseSWIG-guess_module_name' into next

145d653e Help: Add notes for topic 'UseSWIG-guess_module_name'
Merge branch 'release'
Merge branch 'master' into next