Fixes for issues raised by LLVM strict warnings.

[chrismiles]

In our projects we have strict compiler warnings enabled (warnings that are off by default but typically recommended by the Apple LLVM team). This commit updates the source to comply with these strict warnings.

Cheers, Chris

[benoitsan]

What do you mean by LLVM strict warnings, I tried to set -Weverything with your modifications and I still have a lot of warnings.

[chrismiles]

Currently using:

-Werror=incompatible-pointer-types -Werror-implicit-function-declaration -Wmissing-field-initializers -Wmissing-prototypes -Wno-implicit-atomic-properties -Wreceiver-is-weak -Wno-arc-repeated-use-of-weak -Wduplicate-method-match -Wmissing-braces -Wparentheses -Wswitch -Wunused-function -Wno-unused-label -Wunused-parameter -Wunused-variable -Wunused-value -Wempty-body -Wuninitialized -Wunknown-pragmas -Wshadow -Wfour-char-constants -Wconversion -Wconstant-conversion -Wint-conversion -Wbool-conversion -Wenum-conversion -Wsign-compare -Wshorten-64-to-32 -Wpointer-sign -Wnewline-eof -Wselector -Wstrict-selector-match -Wundeclared-selector -Wdeprecated-implementations

Basically, all the practical warnings enabled in Xcode 4.6.3 build settings.