Gentoo's Bugzilla –
Attachment 854920 Details for
Bug 898060net-misc/wput-0.6.2_p20130413_p11 fails to compile (MUSL-CLANG-SYSTEM): memdbg.c:45:9: error: call to undeclared library function exit with type void (int) __attribute__((noreturn)); ISO C99 and later do not support implicit function declarations [-Wimpl