When compiling the source package downloaded from the project page:
backend.c:31: error: static declaration of 'mdb_backends' follows non-static declaration
../../include/mdbtools.h:150: error: previous declaration of 'mdb_backends' was here
mdb_backends has different declarations.
In file include/mdbtools.h:
extern GHashTable *mdb_backends;
In file src/libmdb/backend.c:
static GHashTable *mdb_backends;
The source compiles, and program works, when both are declared static.
My system is a MacOSX 10.4.8, with all the needed libs installed.