exa2pro/starpu-max: porting work to Maxeler DFE @ be1d9c3ece901b669655cf5451df7fbd7e3d2218

Samuel Thibault 3f275cde36 Fix definition of timespec: it is now defined in some w32api version, depending on some obscure toolchain conditions		13 lat temu
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pthread.h	3f275cde36 Fix definition of timespec: it is now defined in some w32api version, depending on some obscure toolchain conditions	13 lat temu
semaphore.h	c6b65fe5f8 re-introduce the thin pthread-to-win32 layer, as an option, as it seems recent versions of mingw and cygwin use a new pthread library which does not play well with starpu.	13 lat temu