Patches adding new configure option --enable-all-static

On the BG/Q machine Mira, we've found that we can't link correctly unless the -all-static flag gets passed to libtool when it's linking, but specifically _after_ the --mode=link directive.  Upon inspection of a number of Makefile.in targets like the following

```
libmesh_dbg_la_LINK = $(LIBTOOL) $(AM_V_lt) --tag=CXX \
	$(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=link $(CXXLD) \
	$(libmesh_dbg_la_CXXFLAGS) $(CXXFLAGS) $(AM_LDFLAGS) \
	$(LDFLAGS) -o $@
```

it seemed like the most appropriate choices were to modify AM_LDFLAGS or LDFLAGS.  Since I read various things warning against modifying LDFLAGS directly (the should be reserved for users) I settled on AM_LDFLAGS.  I'd appreciate it if @benkirk would take a look since I'm still not really an automake expert.  I decided to add a new m4 file rather than adding the function to an existing one, but I can easily change that.