Cannot build: some extern functions couldn't be found

[graysky2]

Trying to build 0.4.0 ends in errors:

% cargo build --release --locked
    Updating crates.io index
 Downloading crates ...
  Downloaded ansi_term v0.11.0
  Downloaded cfg-if v0.1.9
  Downloaded base64 v0.10.1
  Downloaded crossbeam-epoch v0.7.2
  Downloaded crossbeam-queue v0.1.2
  Downloaded semver v0.9.0
  Downloaded semver-parser v0.7.0
  Downloaded textwrap v0.11.0
  Downloaded generic-array v0.12.3
  Downloaded rayon-core v1.6.0
  Downloaded scopeguard v1.0.0
  Downloaded rayon v1.2.0
  Downloaded vec_map v0.8.1
  Downloaded typenum v1.11.2
  Downloaded subtle v2.1.1
  Downloaded rand_hc v0.1.0
  Downloaded rand_chacha v0.1.1
  Downloaded rand_pcg v0.1.2
  Downloaded rustc_version v0.2.3
  Downloaded rand_xorshift v0.1.1
  Downloaded strsim v0.8.0
  Downloaded digest v0.8.1
  Downloaded lazy_static v1.4.0
  Downloaded crossbeam-deque v0.7.1
  Downloaded rand_core v0.3.1
  Downloaded rand_jitter v0.1.4
  Downloaded rand_isaac v0.1.1
  Downloaded rand_core v0.4.2
  Downloaded cc v1.0.45
  Downloaded nodrop v0.1.13
  Downloaded crossbeam-utils v0.6.6
  Downloaded num_cpus v1.10.1
  Downloaded libc v0.2.62
  Downloaded rand_os v0.1.3
  Downloaded rand v0.6.5
  Downloaded either v1.5.3
  Downloaded bitflags v1.1.0
  Downloaded autocfg v0.1.6
  Downloaded memoffset v0.5.1
  Downloaded clap v2.33.0
  Downloaded curve25519-dalek v1.2.3
  Downloaded clear_on_drop v0.2.3
  Downloaded arrayvec v0.4.11
  Downloaded byteorder v1.3.2
  Downloaded unicode-width v0.1.6
  Downloaded atty v0.2.13
  Downloaded x25519-dalek v0.5.2
   Compiling typenum v1.11.2
   Compiling rand_core v0.4.2
   Compiling semver-parser v0.7.0
   Compiling autocfg v0.1.6
   Compiling cc v1.0.45
   Compiling byteorder v1.3.2
   Compiling libc v0.2.62
   Compiling lazy_static v1.4.0
   Compiling arrayvec v0.4.11
   Compiling cfg-if v0.1.9
   Compiling nodrop v0.1.13
   Compiling subtle v2.1.1
   Compiling scopeguard v1.0.0
   Compiling rayon-core v1.6.0
   Compiling bitflags v1.1.0
   Compiling unicode-width v0.1.6
   Compiling ansi_term v0.11.0
   Compiling either v1.5.3
   Compiling vec_map v0.8.1
   Compiling strsim v0.8.0
   Compiling crossbeam-utils v0.6.6
   Compiling textwrap v0.11.0
   Compiling rand_core v0.3.1
   Compiling rand_jitter v0.1.4
   Compiling rand_isaac v0.1.1
   Compiling rand_xorshift v0.1.1
   Compiling rand_hc v0.1.0
   Compiling semver v0.9.0
   Compiling rand_pcg v0.1.2
   Compiling rand_chacha v0.1.1
   Compiling rand v0.6.5
   Compiling crossbeam-queue v0.1.2
   Compiling rustc_version v0.2.3
   Compiling base64 v0.10.1
   Compiling memoffset v0.5.1
   Compiling clear_on_drop v0.2.3
   Compiling num_cpus v1.10.1
   Compiling atty v0.2.13
   Compiling rand_os v0.1.3
   Compiling crossbeam-epoch v0.7.2
   Compiling clap v2.33.0
   Compiling generic-array v0.12.3
   Compiling crossbeam-deque v0.7.1
   Compiling digest v0.8.1
   Compiling curve25519-dalek v1.2.3
   Compiling rayon v1.2.0
   Compiling x25519-dalek v0.5.2
   Compiling wireguard-vanity-address v0.4.0 (/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0)
error: linking with `cc` failed: exit status: 1
  |
  = note: "cc" "-m64" "/tmp/rustcFH2GTM/symbols.o" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/wireguard_vanity_address-947237e50ec05d55.wireguard_vanity_address.943e9611-cgu.0.rcgu.o" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/wireguard_vanity_address-947237e50ec05d55.wireguard_vanity_address.943e9611-cgu.1.rcgu.o" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/wireguard_vanity_address-947237e50ec05d55.wireguard_vanity_address.943e9611-cgu.10.rcgu.o" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/wireguard_vanity_address-947237e50ec05d55.wireguard_vanity_address.943e9611-cgu.11.rcgu.o" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/wireguard_vanity_address-947237e50ec05d55.wireguard_vanity_address.943e9611-cgu.12.rcgu.o" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/wireguard_vanity_address-947237e50ec05d55.wireguard_vanity_address.943e9611-cgu.13.rcgu.o" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/wireguard_vanity_address-947237e50ec05d55.wireguard_vanity_address.943e9611-cgu.14.rcgu.o" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/wireguard_vanity_address-947237e50ec05d55.wireguard_vanity_address.943e9611-cgu.15.rcgu.o" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/wireguard_vanity_address-947237e50ec05d55.wireguard_vanity_address.943e9611-cgu.2.rcgu.o" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/wireguard_vanity_address-947237e50ec05d55.wireguard_vanity_address.943e9611-cgu.3.rcgu.o" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/wireguard_vanity_address-947237e50ec05d55.wireguard_vanity_address.943e9611-cgu.4.rcgu.o" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/wireguard_vanity_address-947237e50ec05d55.wireguard_vanity_address.943e9611-cgu.5.rcgu.o" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/wireguard_vanity_address-947237e50ec05d55.wireguard_vanity_address.943e9611-cgu.6.rcgu.o" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/wireguard_vanity_address-947237e50ec05d55.wireguard_vanity_address.943e9611-cgu.7.rcgu.o" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/wireguard_vanity_address-947237e50ec05d55.wireguard_vanity_address.943e9611-cgu.8.rcgu.o" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/wireguard_vanity_address-947237e50ec05d55.wireguard_vanity_address.943e9611-cgu.9.rcgu.o" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/wireguard_vanity_address-947237e50ec05d55.496s8vqfrrt2zzj9.rcgu.o" "-Wl,--as-needed" "-L" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps" "-L" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/build/clear_on_drop-bb073bce27b800f8/out" "-L" "/usr/lib64/rustlib/x86_64-unknown-linux-gnu/lib" "-Wl,-Bstatic" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/libwireguard_vanity_lib-e30451ea891fad0f.rlib" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/libx25519_dalek-accd0c017bfca8f0.rlib" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/libcurve25519_dalek-99967acaeb1f2cec.rlib" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/libsubtle-8120b5e228cb5e83.rlib" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/libdigest-71b7ae966098005b.rlib" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/libgeneric_array-0df5f426f22a3a18.rlib" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/libtypenum-bacea7cdd87a5dbf.rlib" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/libclear_on_drop-d48bd2923278f2e6.rlib" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/librand-d4979ac11947a5f6.rlib" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/librand_xorshift-029ce742753ab7d7.rlib" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/librand_pcg-aa131745d7a9ec78.rlib" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/librand_hc-b52e548b3305f7b4.rlib" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/librand_chacha-acfc4e8137c7bd30.rlib" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/librand_isaac-76904a22a4a33af5.rlib" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/librand_core-10a462a6d07e5094.rlib" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/librand_os-84084a87f4391114.rlib" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/librand_jitter-54c3ecc6c74da9f3.rlib" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/librand_core-ab12cdb24bdf897c.rlib" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/libbase64-daa7b260cccba74e.rlib" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/libbyteorder-1d4c60549750791e.rlib" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/librayon-5e29a781dfc31a67.rlib" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/librayon_core-01d9eaf1d50654d5.rlib" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/libcrossbeam_queue-6af3cb44bc327a4a.rlib" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/libeither-fd80be35f0fabab6.rlib" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/libcrossbeam_deque-2d48d6945da5e8ae.rlib" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/libcrossbeam_epoch-99506d5e442cd225.rlib" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/libscopeguard-ca5fd9f1f0b6d6ed.rlib" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/libmemoffset-fc7562a6a37b2211.rlib" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/libcrossbeam_utils-beb68f391e5098ba.rlib" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/liblazy_static-3ed758e939fbfa41.rlib" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/libarrayvec-c86a5ae912cd50f6.rlib" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/libnodrop-03281d8bdec646d8.rlib" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/libcfg_if-c492ec102977b467.rlib" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/libnum_cpus-396fcce60a1bb2b7.rlib" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/libclap-986fac8447f2103f.rlib" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/libvec_map-7b061526dc0a9374.rlib" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/libtextwrap-79885264d9f2c0e5.rlib" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/libunicode_width-ef1939beb8565b97.rlib" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/libstrsim-42b655de27d8c4c3.rlib" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/libbitflags-436c04b52ff8056c.rlib" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/libatty-253d52c823f55925.rlib" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/liblibc-5356fdb6f406ace4.rlib" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/libansi_term-122a82c239298c45.rlib" "-Wl,--start-group" "/usr/lib/rustlib/x86_64-unknown-linux-gnu/lib/libstd-9b36e99649387bbe.rlib" "/usr/lib/rustlib/x86_64-unknown-linux-gnu/lib/libpanic_unwind-f57ca554d12f7301.rlib" "/usr/lib/rustlib/x86_64-unknown-linux-gnu/lib/libobject-ba7f0323ff31c2d2.rlib" "/usr/lib/rustlib/x86_64-unknown-linux-gnu/lib/libmemchr-f70666d9c1f600dd.rlib" "/usr/lib/rustlib/x86_64-unknown-linux-gnu/lib/libaddr2line-d96f9507180d65d4.rlib" "/usr/lib/rustlib/x86_64-unknown-linux-gnu/lib/libgimli-e9c2e14fb4ebb299.rlib" "/usr/lib/rustlib/x86_64-unknown-linux-gnu/lib/librustc_demangle-2fbee8f395455027.rlib" "/usr/lib/rustlib/x86_64-unknown-linux-gnu/lib/libstd_detect-e652dffecbe97768.rlib" "/usr/lib/rustlib/x86_64-unknown-linux-gnu/lib/libhashbrown-02feda1e39a291ef.rlib" "/usr/lib/rustlib/x86_64-unknown-linux-gnu/lib/libminiz_oxide-0e0811a51bf70517.rlib" "/usr/lib/rustlib/x86_64-unknown-linux-gnu/lib/libadler-6ddbe538956ea004.rlib" "/usr/lib/rustlib/x86_64-unknown-linux-gnu/lib/librustc_std_workspace_alloc-5cb91feb2e842e02.rlib" "/usr/lib/rustlib/x86_64-unknown-linux-gnu/lib/libunwind-9dbb2ee99cd1c958.rlib" "/usr/lib/rustlib/x86_64-unknown-linux-gnu/lib/libcfg_if-b986f2f65849984b.rlib" "/usr/lib/rustlib/x86_64-unknown-linux-gnu/lib/liblibc-78e00defcd3a9b08.rlib" "/usr/lib/rustlib/x86_64-unknown-linux-gnu/lib/liballoc-e163bcb4c06eb7cf.rlib" "/usr/lib/rustlib/x86_64-unknown-linux-gnu/lib/librustc_std_workspace_core-e2d112e6018ce63c.rlib" "/usr/lib/rustlib/x86_64-unknown-linux-gnu/lib/libcore-436624548804ef9c.rlib" "-Wl,--end-group" "/usr/lib/rustlib/x86_64-unknown-linux-gnu/lib/libcompiler_builtins-8b5f1816a270777a.rlib" "-Wl,-Bdynamic" "-lutil" "-lgcc_s" "-lutil" "-lrt" "-lpthread" "-lm" "-ldl" "-lc" "-Wl,--eh-frame-hdr" "-Wl,-znoexecstack" "-L" "/usr/lib64/rustlib/x86_64-unknown-linux-gnu/lib" "-o" "/build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/wireguard_vanity_address-947237e50ec05d55" "-Wl,--gc-sections" "-pie" "-Wl,-zrelro,-znow" "-Wl,-O1" "-nodefaultlibs"
  = note: /usr/bin/ld: /build/wireguard-vanity-address/src/wireguard-vanity-address-0.4.0/target/release/deps/libx25519_dalek-accd0c017bfca8f0.rlib(x25519_dalek-accd0c017bfca8f0.x25519_dalek.68347b14-cgu.1.rcgu.o): in function `<x25519_dalek::x25519::StaticSecret as core::ops::drop::Drop>::drop':
          x25519_dalek.68347b14-cgu.1:(.text._ZN76_$LT$x25519_dalek..x25519..StaticSecret$u20$as$u20$core..ops..drop..Drop$GT$4drop17h0a44bef031e2e013E+0x14): undefined reference to `clear_on_drop_hide'
          collect2: error: ld returned 1 exit status
          
  = help: some `extern` functions couldn't be found; some native libraries may need to be installed or have their path specified
  = note: use the `-l` flag to specify native libraries to link
  = note: use the `cargo:rustc-link-lib` directive to specify the native libraries to link with Cargo (see https://doc.rust-lang.org/cargo/reference/build-scripts.html#cargorustc-link-libkindname)

error: could not compile `wireguard-vanity-address` due to previous error

[graysky2]

Interestingly, I can build from your 12-count-scalars branch without errors.