src/phobos/linux.mak STD_MODULES definition (line 122) is missing "exception" in the list of module names. libphobos2.a builds without it, but if you try to link against the resulting library, it becomes obvious you won't get very far without it.
Other phobos modules are not listed, although some of these omissions may be deliberate. Here's the list; you decide.
Other std modules missing from STD_MODULES:
atomics
bind (related to Issue 3778 ?)
bitarray (replaced by bitmanip)
__fileinit
iterator
openrj
stdarg
Comment #1 by ghaecker — 2010-09-17T22:29:07Z
Patch submitted on issue #4459 adds missing exception module name to STD_MODULES. The patch does not address the other missing modules cited in this issue.
Comment #2 by witold.baryluk+d — 2010-11-26T13:19:34Z
*** Issue 5267 has been marked as a duplicate of this issue. ***
Comment #3 by andrei — 2016-12-22T14:30:20Z
Fixed long ago, in all likelihood closing this was overlooked.