I am getting consistently the link error building lang/rust using current pkgsrc and very new amd64 -current:
=> Bootstrap dependency digest>=20010302: found digest-20160304
===> Building for rust-1.11.0
cfg: version 1.11.0
cfg: build triple x86_64-unknown-netbsd
cfg: host triples x86_64-unknown-netbsd
cfg: target triples x86_64-unknown-netbsd
cfg: host for x86_64-unknown-netbsd is x86_64
cfg: os for x86_64-unknown-netbsd is unknown-netbsd
cfg: no good valgrind for x86_64-unknown-netbsd
cfg: disabling valgrind run-pass tests
cfg: disabling unstable features (CFG_DISABLE_UNSTABLE_FEATURES)
cfg: disabling doc build (CFG_DISABLE_DOCS)
rustc: x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/bin/rustc
error: linking with `cc` failed: exit code: 1
note: "cc" "-Wl,--as-needed" "-Wl,-z,noexecstack" "-m64" "-L" "/usr/pkgsrc/lang/rust/work/rustc-1.11.0/x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/lib" "x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/bin/rustc.0.o" "-o" "x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/bin/rustc" "-Wl,--gc-sections" "-pie" "-Wl,-O1" "-nodefaultlibs" "-L" "/usr/pkg/lib" "-L" "/usr/pkgsrc/lang/rust/work/rustc-1.11.0/x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/lib" "-Wl,-Bstatic" "-Wl,-Bdynamic" "-L" "/usr/pkgsrc/lang/rust/work/rustc-1.11.0/x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/lib" "-l" "rustc_driver-39b92f95" "-L" "/usr/pkgsrc/lang/rust/work/rustc-1.11.0/x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/lib" "-l" "syntax_ext-39b92f95" "-L" "/usr/pkgsrc/lang/rust/work/rustc-1.11.0/x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/lib" "-l" "rustc_save_analysis-39b92f95" "-L" "/usr/pkgsrc/lang/rust/work/rustc-1.11.0/x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/lib" "-l" "rustc_privacy-39b92f95" "-L" "/usr/pkgsrc/lang/rust/work/rustc-1.11.0/x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/lib" "-l" "rustc_trans-39b92f95" "-L" "/usr/pkgsrc/lang/rust/work/rustc-1.11.0/x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/lib" "-l" "rustc_passes-39b92f95" "-L" "/usr/pkgsrc/lang/rust/work/rustc-1.11.0/x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/lib" "-l" "rustc_typeck-39b92f95" "-L" "/usr/pkgsrc/lang/rust/work/rustc-1.11.0/x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/lib" "-l" "rustc_borrowck-39b92f95" "-L" "/usr/pkgsrc/lang/rust/work/rustc-1.11.0/x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/lib" "-l" "rustc_mir-39b92f95" "-L" "/usr/pkgsrc/lang/rust/work/rustc-1.11.0/x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/lib" "-l" "rustc_plugin-39b92f95" "-L" "/usr/pkgsrc/lang/rust/work/rustc-1.11.0/x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/lib" "-l" "rustc_metadata-39b92f95" "-L" "/usr/pkgsrc/lang/rust/work/rustc-1.11.0/x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/lib" "-l" "rustc_resolve-39b92f95" "-L" "/usr/pkgsrc/lang/rust/work/rustc-1.11.0/x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/lib" "-l" "rustc_platform_intrinsics-39b92f95" "-L" "/usr/pkgsrc/lang/rust/work/rustc-1.11.0/x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/lib" "-l" "rustc_lint-39b92f95" "-L" "/usr/pkgsrc/lang/rust/work/rustc-1.11.0/x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/lib" "-l" "rustc_const_eval-39b92f95" "-L" "/usr/pkgsrc/lang/rust/work/rustc-1.11.0/x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/lib" "-l" "rustc_incremental-39b92f95" "-L" "/usr/pkgsrc/lang/rust/work/rustc-1.11.0/x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/lib" "-l" "rustc-39b92f95" "-L" "/usr/pkgsrc/lang/rust/work/rustc-1.11.0/x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/lib" "-l" "rustc_data_structures-39b92f95" "-L" "/usr/pkgsrc/lang/rust/work/rustc-1.11.0/x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/lib" "-l" "rustc_const_math-39b92f95" "-L" "/usr/pkgsrc/lang/rust/work/rustc-1.11.0/x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/lib" "-l" "rustc_back-39b92f95" "-L" "/usr/pkgsrc/lang/rust/work/rustc-1.11.0/x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/lib" "-l" "flate-39b92f95" "-L" "/usr/pkgsrc/lang/rust/work/rustc-1.11.0/x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/lib" "-l" "rbml-39b92f95" "-L" "/usr/pkgsrc/lang/rust/work/rustc-1.11.0/x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/lib" "-l" "getopts-39b92f95" "-L" "/usr/pkgsrc/lang/rust/work/rustc-1.11.0/x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/lib" "-l" "rustc_llvm-39b92f95" "-L" "/usr/pkgsrc/lang/rust/work/rustc-1.11.0/x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/lib" "-l" "syntax-39b92f95" "-L" "/usr/pkgsrc/lang/rust/work/rustc-1.11.0/x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/lib" "-l" "arena-39b92f95" "-L" "/usr/pkgsrc/lang/rust/work/rustc-1.11.0/x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/lib" "-l" "rustc_errors-39b92f95" "-L" "/usr/pkgsrc/lang/rust/work/rustc-1.11.0/x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/lib" "-l" "syntax_pos-39b92f95" "-L" "/usr/pkgsrc/lang/rust/work/rustc-1.11.0/x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/lib" "-l" "serialize-39b92f95" "-L" "/usr/pkgsrc/lang/rust/work/rustc-1.11.0/x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/lib" "-l" "log-39b92f95" "-L" "/usr/pkgsrc/lang/rust/work/rustc-1.11.0/x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/lib" "-l" "term-39b92f95" "-L" "/usr/pkgsrc/lang/rust/work/rustc-1.11.0/x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/lib" "-l" "graphviz-39b92f95" "-L" "/usr/pkgsrc/lang/rust/work/rustc-1.11.0/x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/lib" "-l" "fmt_macros-39b92f95" "-L" "/usr/pkgsrc/lang/rust/work/rustc-1.11.0/x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/lib" "-l" "std-39b92f95" "-l" "rt" "-l" "terminfo" "-l" "pthread" "-l" "z" "-l" "m" "-l" "stdc++" "-l" "pthread" "-l" "gcc" "-l" "c" "-l" "m" "-l" "rt" "-l" "util" "-Wl,-rpath,$ORIGIN/../lib" "-Wl,-rpath,/usr/local/lib/rustlib/x86_64-unknown-netbsd/lib" "-Wl,--enable-new-dtags" "-l" "compiler-rt"
note: /usr/pkgsrc/lang/rust/work/rustc-1.11.0/x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/lib/librustc_trans-39b92f95.so: undefined reference to `LLVMWriteBitcodeToFile'
/usr/pkgsrc/lang/rust/work/rustc-1.11.0/x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/lib/librustc_trans-39b92f95.so: undefined reference to `LLVMRustAddLibraryInfo'
/usr/pkgsrc/lang/rust/work/rustc-1.11.0/x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/lib/librustc_trans-39b92f95.so: undefined reference to `LLVMPassManagerBuilderCreate'
..........................
/usr/pkgsrc/lang/rust/work/rustc-1.11.0/x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/lib/librustc_trans-39b92f95.so: undefined reference to `LLVMPassManagerBuilderPopulateModulePassManager'
error: aborting due to previous error
/usr/pkgsrc/lang/rust/work/rustc-1.11.0/mk/
target.mk:220: recipe for target 'x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/bin/rustc' failed
gmake: *** [x86_64-unknown-netbsd/stage0/lib/rustlib/x86_64-unknown-netbsd/bin/rustc] Error 101
*** Error code 2
Stop.
make[1]: stopped in /usr/pkgsrc/lang/rust
*** Error code 1
Stop.
make: stopped in /usr/pkgsrc/lang/rust