[Pkg-octave-devel] Bug#383149: Found the cause.

[John Dalton]

I've got a program called OpenFOAM installed.  It's
a bit of a yukky program in that it sets some environment
variables in ~/.bashrc.  Consequently the environment of my
login shell looks like:

{lots of stuff deleted}
CXXFLAGS=-m32
CXX=g++

When mkoctfile evaluates CXXFLAGS and CXX, it sees the values
from my shell environment, not the values being set within
mkoctfile (CXX="/usr/bin/g++" and CXXFLAGS="-O2")

That explains the weird appearance of g++ and -m32.

Is it correct that existing values in the shell environment should 
override the default values within mkoctfile?  Is there a reason
mkoctfile reads
: ${LD_CXX="/usr/bin/g++"}
instead of
LD_CXX="/usr/bin/g++"

I don't really understand what
: ${variable="value"}
is doing.  Can someone please explain it to me?


I guess one solution is for me to remove the
variables from my environment, but is this
behaviour that the authors of mkoctfile intended?