If emerging -e system on PPC, libperl can't find libndbm, which is located in sys-libs/db-1.85. This special lib seems not to be contained in later db-versions. So I had to emerge sys-libs/db-1.85-r1 as db-1.85-r2 is masked in PPC. Another issue is, that db-1.85-r1 uses cc as the compiler and this is not acceptable for cross compiling. The ebuild should contain a line that points CC to the appropriate compiler. If done with CC=/usr/bin/ppc-somewhat-linux-gnu-gcc ... emerge sys-libs/db-1.85-r1
Reopen with some errors and emerge --info. Plus, your db issue is completely separate and unrelated, file a new bug.
Sorry, cannot give more information because of broken glibc (http://bugs.gentoo.org/show_bug.cgi?id=149144) that brought me in trouble. Until it is fixed, I have no possibility to submit more information. But after this I will do...