Why does static-gnulib include -lgcc_eh?

[Bryan Ischo <bryan at ischo dot com>]

Hello.  gcc builds libgcc_sh according to these rules in its 
libgcc/Makefile:

> ifeq ($(enable_shared),yes)
>
> libgcc-eh-objects += $(addsuffix $(objext),$(basename $(notdir 
$(LIB2ADDEHSTATIC))))
> libgcc-s-objects += $(addsuffix _s$(objext),$(basename $(notdir 
$(LIB2ADDEHSHARED))))
>
> iter-items := $(sort $(LIB2ADDEHSTATIC) $(LIB2ADDEHSHARED))
> include $(iterator)
>
> else
> # Not shared.  LIB2ADDEH are added to libgcc.a.
>
> libgcc-objects += $(addsuffix $(objext),$(basename $(notdir 
$(LIB2ADDEH))))
>
> iter-items := $(LIB2ADDEH)
> include $(iterator)
>
> endif

Note that if enabled_shared is set to yes, then libgcc-eh is built; 
otherwise, it is added to libgcc.  And this confirms what I am seeing, 
which is that gcc built with --disable-shared does not produce a 
libgcc_eh.a (totally weird that if shared is enabled, libgcc_eh.a, which 
is not a shared library, does get built).

Now glibc has this in its Makeconfig:

# The static libraries.
ifeq (yes,$(build-static))
link-libc-static = $(common-objpfx)libc.a $(static-gnulib) 
$(common-objpfx)libc.a
else
ifeq (yes,$(build-shared))
# We can try to link the programs with lib*_pic.a...
link-libc-static = $(static-gnulib) $(common-objpfx)libc_pic.a
endif
endif
link-libc-bounded = $(common-objpfx)libc_b.a $(gnulib) 
$(common-objpfx)libc_b.a

ifndef gnulib
ifneq ($(have-cc-with-libunwind),yes)
  libunwind =
else
  libunwind = -lunwind
endif
ifneq ($(have-as-needed),yes)
 libgcc_eh := -lgcc_eh $(libunwind)
else
 libgcc_eh := -Wl,--as-needed -lgcc_s$(libgcc_s_suffix) $(libunwind) 
-Wl,--no-as-needed
endif
gnulib := -lgcc $(libgcc_eh)
static-gnulib := -lgcc -lgcc_eh $(libunwind)
libc.so-gnulib := -lgcc
endif

Note that static-gnulib is set to include -lgcc_eh; but doesn't this 
conflict with gcc's Makefile?  If gcc was built statically, then 
libgcc_eh.a does not exist and glibc should only include -lgcc.

I'm thinking that maybe it's actually something that should be detected; 
glibc doesn't know if gcc built libgcc_eh.a or not and probably 
shouldn't be assuming that it did; I think that if gcc was built with 
shared libraries then there will be a separate libgcc.a and libgcc_eh.a, 
but if not, then there will only be libgcc.a.  Whether or not glibc is 
building shared libraries, static libraries or whatever, I don't think 
it should be assuming what libraries are available from gcc since gcc 
can produce different libraries under different build configurations.

Thanks,
Bryan