When compiling WORKSHARE construct in different compilation units, a
linker error happened, when two equal WORKSHARE constructs with a copy
operation have been compiled:
```
/usr/bin/ld: module2.o: in function `_workshare_copy_f64':
FIRModule:(.text+0x0): multiple definition of `_workshare_copy_f64'; module1.o:FIRModule:(.text+0x0): first defined here
```
Reason is that the generate copy function has the wrong linkage:
```
0000000000000000 T _workshare_copy_f64
```
while it should be
```
0000000000000000 t _workshare_copy_f64
```
Add a new pass that lowers an `omp.workshare` with its binding `omp.workshare.loop_wrapper` loop nests into other OpenMP constructs that can be lowered to LLVM.
More specifically, in order to preserve the sequential execution semantics of the code contained, it wraps portions that needs to be executed on a single thread in `omp.single` blocks, converts code that must be parallelized into `omp.wsloop` nests and inserts the appropriate synchronization.
