Unexpected behavior when using algorithm::trim() to remove spaces

The issue comes from boostorg/compute#817 where `boost::trim()` is invoked to sanitize OpenCL kernel arguments from preprocessor-generated strings. One of the failing cases taken directly from the boost compute repo is this:

```c++
two, pi // original string
[two, pi] // vector after split() using comma as delimiter
two // first element after trim()
p // second element after trim()
```
Here the `trim()` actually leave a leading space left of `pi` and slices one valid character on the right. One big BUT: this only happens to Linux cross-compiler targeting Android platform, downloaded from Android NDK page. Where as MSVC on Windows, GCC/Clang on Mac all run without problems. What might be the reason of this unexpected behavior?

Comienza con algorithm::trim() y reproduce el ejemplo de división por comas de boostorg/compute#817 utilizando el compilador cruzado de Linux del Android NDK. Compara su comportamiento con MSVC en Windows y GCC/Clang en macOS para aislar la causa específica de la plataforma. Se considera terminado cuando se haya explicado la causa y se haya corregido la salida indicada sin regresiones.

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