LLVM libxcrypt symbols

[GekkoNZ]

I'm having a problem compiling libxcrypt with clang/llvm on a systemd/llvm profile

libxcrypt appears to compile but the library doesn't contain certain symbols such as:
crypt_gensalt
crypt
crypt_rn
crypt_ra
crypt_r
crypt_gensalt_rn
crypt_gensalt_ra
crypt_checksalt
crypt_preferred_method

Compiling things like pam and shadow fail because of this.

COMMON_FLAGS="-march=x86-64-v3 -mtune=znver3 -O2 -pipe -fomit-frame-pointer -flto=thin"
LDFLAGS="${LDFLAGS} -Wl,--undefined-version"

GNU toolchain compiles this just fine with the same flags

Any advice appreciated.