From Ron:
Hi,
on the mac, the nightly download is about 280MB This is very massive.

Is there a meaningful way to reduce the size of the download?

From Julien:
It's large indeed, I could argue on the "very massive" term but I won't :-)
For comparison, the linux package is 700mo and the windows builds are now around 150mo.
The packages used to be smaller in August/September (windows builds were as small as 80mo).
When I look inside the the content of the mac package, I don't really see anything useless that is wasting space.

I suspect the inclusion of EMSegment + BrainstTools inside the package (instead of being extensions (our goal)) is partly responsible for the increase.

Now, we can probably configure the c++ compiler to optimize the size of the libraries, but I'm not sure how much space we will get back.
Before we do that, I've noticed that you experienced some asserts in the past, I wonder if that means that some libs in Slicer are compiled in Debug mode, which takes more memory space.
I guess all of what I'm saying is that it would need some more investigation which can be time consuming, your call in deciding if it worth it.

My preference would be to cleanup the linux package first.

From Jc:
On linux, the --visibility=hidden flag should be added. This is something I had on my list.

"It reduces the size of your DSO by 5-20%. ELF's exported symbol table format is quite a space hog, giving the complete mangled symbol name which with heavy template usage can average around 1000 bytes. C++ templates spew out a huge amount of symbols and a typical C++ library can easily surpass 30,000 symbols which is around 5-6Mb! Therefore if you cut out the 60-80% of unnecessary symbols, your DSO can be megabytes smaller! "

See http://gcc.gnu.org/wiki/Visibility