• Apps may compile with optimizations for Linux only. eg:
Oh, ha ha ha
• #ifdef Linux -O3 #else -O0
• Developers are often writing software on Linux, and that
platform gets the most attention. (Works on my system.)
• I've also seen 64-bit vs 32-bit. #ifdef Linux USE_FUTEX would
be ﬁne, since Solaris doesn't have them yet.
• Last time I found compiler differences using Flame Graphs: