libpng 1.2.5-r8 compiles, installs, and merges fine into Mac OS X. Reported as suggested by the Gentoo for Mac OS X Wiki.
Steps to Reproduce:
ACCEPT_KEYWORDS="macos ~macos ppc ~ppc" emerge libpng
*** Bug 62072 has been marked as a duplicate of this bug. ***
Fixed in CVS. (use invocations had been broken after the keyword change)
Closing out bugs that've been resolved for a while now...