Fixed undefined shift into sign bit

It is undefined behaviour to shift a 1 into a signed integer's
high bit. Simple fix: add 'U' suffix.

Warned by clang's -Weverything.

Change-Id: I59a64975c034ebd1ce4d7c6f7b3340a0fa12ea5c
Fixed various clang -Wundef warnings

Use #ifdef instead of just #if to fix some -Wundef warnings.
In most cases, this just makes things more consistent with
existing code.

Change-Id: I7aec13b54793de4e85eedcfe94cde83a147b217b
Silence warning about possible uninitialized use

Just set initial value to 0 to silence warning.

Change-Id: I0c47e5ef9570c57b77dd7cd8564389fd846999c1
Removed dead code to fix -Wundef warning

Code wrapped in "#if VTK3", from its name, seems obsolete.
There is no other instance of "VTK3" in the codebase.

Change-Id: I1f415c32e5d4769a7152209453f48d724d9d27a8
Made various private functions static to fix warnings

Fixes a few clang -Wmissing-prototypes warnings.

Change-Id: I7556172dd3f1049a38926057abe16b1bdad78126
Merge topic 'Weverything' into master

a2a51f79 Made various private functions static to fix warnings
2d5ef908 Removed dead code to fix -Wundef warning
6e96142f Silence warning about possible uninitialized use
0b992282 Fixed various clang -Wundef warnings
a091d0f5 Fixed undefined shift into sign bit