I got an email at work today, which had a couple lines of g++ calls, which Outlook displayed to me like this:

g++ -o exe1 -DXYZ=abc maintemplate.cpp test001.cpp -o exe2 -DXYZ=def
g++  maintemplate.cpp test002.cpp

Turns out, this was because it “removed extra linebreaks” (which works fine most of the time, but its terrible in some cases). The original was:

g++ -o exe1 -DXYZ=abc maintemplate.cpp test001.cpp
g++ -o exe2 -DXYZ=def maintemplate.cpp test002.cpp

Sigh. I guess it tries to recognized common prefixes or something.