Linking D code into existing C programs

[Walter Bright via Digitalmars-d]

Linking C libraries and object code into D programs has always worked easily in 
D. The other way around, not so well.

Consider the following C program:

   ---- main.c ----
   extern int foo();
   void main(int argc, char* argv[]) {
     foo();
   }
   ---- foo.c ----
   int foo() { return 7; }
   ---------------

Compile/link in the usual way:

     gcc main.c -c
     gcc foo.c -c
     gcc main.o foo.o

No problem.
Now replace foo.c with foo.d:

   ---- foo.d ----
   extern (C) int foo() { return 7; }
   ---------------

Compile/link with:

     gcc main.c -c
     dmd foo.d -c
     gcc main.o foo.o

Produces:

   bar.o:(.eh_frame+0x13): undefined reference to `__dmd_personality_v0'
   bar.o: In function `_D3bar7__arrayZ':
   bar.d:(.text._D3bar7__arrayZ+0x21): undefined reference to `_d_arraybounds'
   bar.o: In function `_D3bar8__assertFiZv':
   bar.d:(.text._D3bar8__assertFiZv+0x21): undefined reference to `_d_assert'
   bar.o: In function `_D3bar15__unittest_failFiZv':
   bar.d:(.text._D3bar15__unittest_failFiZv+0x21): undefined reference to 
`_d_unittest'
   bar.o: In function `__d_dso_init':
   bar.d:(.text.d_dso_init[.data.d_dso_rec]+0x28): undefined reference to 
`_d_dso_registry'
   collect2: error: ld returned 1 exit status

How much of an issue is this with D? Is it something we need to address?