我一直在尝试build the Canvas Data Loader。我已经走到第10步了，解决cargo build fail上的依赖关系非常容易，但是在过去的4天里，我一直无法解决librocksdb-sys v5.14.2的依赖关系：
[root@localhost home]# gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-redhat-linux/4.8.5/lto-wrapper
Target: x86_64-redhat-linux
Configured with: ../configure --prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info --with-bugurl=http://bugzilla.redhat.com/bugzilla --enable-bootstrap --enable-shared --enable-threads=posix --enable-checking=release --with-system-zlib --enable-__cxa_atexit --disable-libunwind-exceptions --enable-gnu-unique-object --enable-linker-build-id --with-linker-hash-style=gnu --enable-languages=c,c++,objc,obj-c++,java,fortran,ada,go,lto --enable-plugin --enable-initfini-array --disable-libgcj --with-isl=/builddir/build/BUILD/gcc-4.8.5-20150702/obj-x86_64-redhat-linux/isl-install --with-cloog=/builddir/build/BUILD/gcc-4.8.5-20150702/obj-x86_64-redhat-linux/cloog-install --enable-gnu-indirect-function --with-tune=generic --with-arch_32=x86-64 --build=x86_64-redhat-linux
Thread model: posix
gcc version 4.8.5 20150623 (Red Hat 4.8.5-28) (GCC)
[root@localhost home]# rustc -V
rustc 1.30.0 (da5f414c2 2018-10-24)
[root@localhost home]# rustup -V
rustup 1.14.0 (1e51b07cc 2018-10-04)
[root@localhost home]# rustup show
Default host: x86_64-unknown-linux-gnu
stable-x86_64-unknown-linux-gnu (default)
rustc 1.30.0 (da5f414c2 2018-10-24)
[root@localhost home]# cargo build --release
Compiling gcc v0.3.55
Compiling bit-vec v0.4.4
Compiling rustc-demangle v0.1.9
Compiling percent-encoding v1.0.1
Compiling linked-hash-map v0.5.1
Compiling language-tags v0.2.2
Compiling smallvec v0.4.5
Compiling uuid v0.5.1
Compiling sha1 v0.2.0
Compiling bufstream v0.1.4
Compiling fnv v1.0.6
Compiling untrusted v0.5.1
Compiling crossbeam-utils v0.2.2
Compiling log v0.4.5
Compiling arrayvec v0.4.7
Compiling num_cpus v1.8.0
Compiling iovec v0.1.2
Compiling net2 v0.2.33
Compiling memchr v1.0.2
Compiling atty v0.2.11
Compiling rand v0.4.3
Compiling which v1.0.5
Compiling time v0.1.40
Compiling socket2 v0.3.8
Compiling lazy_static v1.1.0
Compiling memchr v2.1.0
Compiling unicase v2.2.0
Compiling semver v0.9.0
Compiling unreachable v1.0.0
Compiling owning_ref v0.3.3
Compiling rand_core v0.2.2
Compiling regex-syntax v0.6.2
Compiling regex-syntax v0.5.6
Compiling proc-macro2 v0.3.5
Compiling clang-sys v0.23.0
Compiling textwrap v0.10.0
Compiling humantime v1.1.1
Compiling tokio-executor v0.1.5
Compiling tokio-service v0.1.0
Compiling relay v0.1.1
Compiling block-buffer v0.3.3
Compiling unicode-bidi v0.3.4
Compiling phf_shared v0.7.23
Compiling foreign-types v0.3.2
Compiling base64 v0.6.0
Compiling base64 v0.7.0
Compiling nix v0.9.0
Compiling base64 v0.9.3
Compiling scheduled-thread-pool v0.1.0
Compiling serde_test v0.8.23
Compiling yaml-rust v0.4.2
Compiling log v0.3.9
Compiling want v0.0.4
Compiling bytes v0.4.10
Compiling futures-cpupool v0.1.8
Compiling nom v3.2.1
Compiling mio v0.6.16
Compiling rand v0.3.22
Compiling smallvec v0.6.5
Compiling rand v0.5.5
Compiling lock_api v0.1.4
Compiling rustc_version v0.2.3
Compiling quote v0.5.2
Compiling clap v2.32.0
Compiling tokio-current-thread v0.1.3
Compiling tokio-timer v0.2.7
Compiling phf v0.7.23
Compiling stringprep v0.1.2
Compiling idna v0.1.5
Compiling linked-hash-map v0.3.0
Compiling r2d2 v0.7.4
Compiling tokio-io v0.1.10
Compiling generic-array v0.9.0
Compiling mio-uds v0.6.7
Compiling parking_lot_core v0.3.1
Compiling cexpr v0.2.3
Compiling twox-hash v1.1.1
Compiling atoi v0.2.3
Compiling num-traits v0.1.43
Compiling serde_json v1.0.32
Compiling toml v0.4.8
Compiling quote v0.6.8
Compiling tokio-codec v0.1.1
Compiling crossbeam-epoch v0.3.1
Compiling crossbeam-epoch v0.5.2
Compiling thread_local v0.3.6
Compiling url v1.7.1
Compiling digest v0.7.6
Compiling crypto-mac v0.5.2
Compiling aho-corasick v0.6.8
Compiling mime v0.3.12
Compiling chrono v0.4.6
Compiling crossbeam-deque v0.2.0
Compiling syn v0.15.13
Compiling crossbeam-deque v0.6.1
Compiling sha2 v0.7.1
Compiling hmac v0.5.0
Compiling tokio-threadpool v0.1.8
Compiling postgres-protocol v0.3.2
Compiling parking_lot v0.6.4
Compiling rayon v0.8.2
Compiling mysql_common v0.5.0
Compiling serde_derive v1.0.80
Compiling env_logger v0.5.13
Compiling serde-hjson v0.8.2
Compiling tokio-reactor v0.1.6
Compiling tokio-fs v0.1.4
Compiling postgres-shared v0.4.2
Compiling ring v0.12.1
Compiling cc v1.0.25
Compiling tokio-tcp v0.1.2
Compiling tokio-udp v0.1.2
Compiling tokio-uds v0.2.3
Compiling config v0.8.0
Compiling postgres v0.15.2
Compiling libloading v0.5.0
Compiling openssl-sys v0.9.39
Compiling backtrace-sys v0.1.24
Compiling libz-sys v1.0.25
Compiling tokio v0.1.11
Compiling r2d2_postgres v0.13.0
Compiling tokio-core v0.1.17
Compiling flate2 v0.2.20
Compiling backtrace v0.3.9
Compiling tokio-proto v0.1.1
Compiling error-chain v0.11.0
Compiling hyper v0.11.27
Compiling native-tls v0.1.5
Compiling mysql v12.3.1
Compiling tokio-tls v0.1.4
Compiling hyper-tls v0.1.4
Compiling librocksdb-sys v5.14.2
error: failed to run custom build command for `librocksdb-sys v5.14.2`
process didn't exit successfully: `/user1/home/target/release/build/librocksdb-sys-56635e7b678cd86e/build-script-build` (exit code: 101)
--- stdout
cargo:rerun-if-changed=build.rs
cargo:rerun-if-changed=rocksdb/
cargo:rerun-if-changed=snappy/
--- stderr
thread 'main' panicked at 'Unable to find libclang: "couldn\'t find any of [\'libclang.so\', \'libclang.so.*\', \'libclang-*.so\'], set the LIBCLANG_PATH environment variable to a path where one of these files can be found (skipped: [])"', libcore/result.rs:1009:5
note: Run with `RUST_BACKTRACE=1` for a backtrace.
我跟随these instructions安装clang，然后跟随these instructions通过clang构建libcxx。
再次尝试构建时，出现以下错误：
Compiling librocksdb-sys v5.14.2
error: failed to run custom build command for `librocksdb-sys v5.14.2`
process didn't exit successfully: `/user1/home/target/release/build/librocksdb-sys-56635e7b678cd86e/build-script-build` (exit code: 101)
--- stdout
cargo:rerun-if-changed=build.rs
cargo:rerun-if-changed=rocksdb/
cargo:rerun-if-changed=snappy/
TARGET = Some("x86_64-unknown-linux-gnu")
OPT_LEVEL = Some("3")
HOST = Some("x86_64-unknown-linux-gnu")
CXX_x86_64-unknown-linux-gnu = None
CXX_x86_64_unknown_linux_gnu = None
HOST_CXX = None
CXX = None
CXXFLAGS_x86_64-unknown-linux-gnu = None
CXXFLAGS_x86_64_unknown_linux_gnu = None
HOST_CXXFLAGS = None
CXXFLAGS = None
DEBUG = Some("false")
running: "c++" "-O3" "-ffunction-sections" "-fdata-sections" "-fPIC" "-m64" "-I" "rocksdb/include/" "-I" "rocksdb/" "-I" "rocksdb/third-party/gtest-1.7.0/fused-src/" "-I" "snappy/" "-I" "." "-Wall" "-Wextra" "-std=c++11" "-Wno-unused-parameter" "-DNDEBUG=1" "-DSNAPPY=1" "-DOS_LINUX=1" "-DROCKSDB_PLATFORM_POSIX=1" "-DROCKSDB_LIB_IO_POSIX=1" "-o" "/user1/home/target/release/build/librocksdb-sys-fe80efb4608df839/out/rocksdb/utilities/blob_db/blob_log_format.o" "-c" "rocksdb/utilities/blob_db/blob_log_format.cc"
running: "c++" "-O3" "-ffunction-sections" "-fdata-sections" "-fPIC" "-m64" "-I" "rocksdb/include/" "-I" "rocksdb/" "-I" "rocksdb/third-party/gtest-1.7.0/fused-src/" "-I" "snappy/" "-I" "." "-Wall" "-Wextra" "-std=c++11" "-Wno-unused-parameter" "-DNDEBUG=1" "-DSNAPPY=1" "-DOS_LINUX=1" "-DROCKSDB_PLATFORM_POSIX=1" "-DROCKSDB_LIB_IO_POSIX=1" "-o" "/user1/home/target/release/build/librocksdb-sys-fe80efb4608df839/out/rocksdb/table/full_filter_block.o" "-c" "rocksdb/table/full_filter_block.cc"
running: "c++" "-O3" "-ffunction-sections" "-fdata-sections" "-fPIC" "-m64" "-I" "rocksdb/include/" "-I" "rocksdb/" "-I" "rocksdb/third-party/gtest-1.7.0/fused-src/" "-I" "snappy/" "-I" "." "-Wall" "-Wextra" "-std=c++11" "-Wno-unused-parameter" "-DNDEBUG=1" "-DSNAPPY=1" "-DOS_LINUX=1" "-DROCKSDB_PLATFORM_POSIX=1" "-DROCKSDB_LIB_IO_POSIX=1" "-o" "/user1/home/target/release/build/librocksdb-sys-fe80efb4608df839/out/rocksdb/utilities/merge_operators/bytesxor.o" "-c" "rocksdb/utilities/merge_operators/bytesxor.cc"
running: "c++" "-O3" "-ffunction-sections" "-fdata-sections" "-fPIC" "-m64" "-I" "rocksdb/include/" "-I" "rocksdb/" "-I" "rocksdb/third-party/gtest-1.7.0/fused-src/" "-I" "snappy/" "-I" "." "-Wall" "-Wextra" "-std=c++11" "-Wno-unused-parameter" "-DNDEBUG=1" "-DSNAPPY=1" "-DOS_LINUX=1" "-DROCKSDB_PLATFORM_POSIX=1" "-DROCKSDB_LIB_IO_POSIX=1" "-o" "/user1/home/target/release/build/librocksdb-sys-fe80efb4608df839/out/rocksdb/cache/clock_cache.o" "-c" "rocksdb/cache/clock_cache.cc"
--- stderr
rocksdb/include/rocksdb/c.h:48:9: warning: #pragma once in main file, err: false
thread 'main' panicked at '
Internal error occurred: Failed to find tool. Is `c++` installed?
', /root/.cargo/registry/src/github.com-1ecc6299db9ec823/cc-1.0.25/src/lib.rs:2260:5
note: Run with `RUST_BACKTRACE=1` for a backtrace.
c++安装在/usr/include/c++