Fix various non-standards compliant code when compiled with elevated warning levels (-Wall -Wpedantic). Here is a list of the problems addressed:

**preprocessor**
- expansion of empty `__VA_ARGS__` in `ARB_PP_FOREACH`
- named variadic macro arguments in `TRACE` macro

**glibc** 
- deprecated `mallinfo` call for newer glibc versions

**simd**
- non-const C-array sizes

**modcc**
- generation of C-arrays of size 0

**switch/case**
- switch-case ranges

**tuple_foreach**
- compound literals