Created attachment 429126 [details, diff]
A patch to fix the problem.
sys-libs/timezone-data tries to link programs with libintl with USE=nls and not with glibc. However, this causes a link error on musl profile because the built-in libintl is used on that profile. Just checking elibc_musl works well.
I've confirmed with 2015g and 2016a.
> x86_64-gentoo-linux-musl-gcc -o zic -O2 -pipe -std=gnu99 -Wl,-O1 -Wl,--as-needed zic.o -lintl
> /usr/lib/gcc/x86_64-gentoo-linux-musl/4.9.3/../../../../x86_64-gentoo-linux-musl/bin/ld: cannot find -lintl
> collect2: error: ld returned 1 exit status
> Makefile:401: recipe for target 'zic' failed
> make: *** [zic] Error 1
*** Bug 579104 has been marked as a duplicate of this bug. ***