title: Cant install allennlp with pip on mac
body: <p>I am trying to install allennlp on my mac. I have tried installing macOS headers which solved the missing headers problem but now i am experiencing new problems. </p>
  
  <p>The error when i run <code>pip install allennlp</code>:</p>
  
  <pre><code>Running setup.py bdist_wheel for jsonnet ... error
    Complete output from command /anaconda3/bin/python -u -c "import setuptools, tokenize;__file__='/private/var/folders/qf/jkn4v43j08xgst0r9yxyl0dc0000gn/T/pip-install-i4nyb384/jsonnet/setup.py';f=getattr(tokenize, 'open', open)(__file__);code=f.read().replace('\r\n', '\n');f.close();exec(compile(code, __file__, 'exec'))" bdist_wheel -d /private/var/folders/qf/jkn4v43j08xgst0r9yxyl0dc0000gn/T/pip-wheel-eof7cc6k --python-tag cp37:
    running bdist_wheel
    running build
    running build_ext
    x86_64-apple-darwin13.4.0-clang++ -c -march=core2 -mtune=haswell -mssse3 -ftree-vectorize -fPIC -fPIE -fstack-protector-strong -O2 -pipe -stdlib=libc++ -fvisibility-inlines-hidden -std=c++14 -fmessage-length=0 core/desugarer.cpp -o core/desugarer.o
    In file included from core/desugarer.cpp:17:
    In file included from /Library/Developer/CommandLineTools/usr/include/c++/v1/cassert:21:
    In file included from /Library/Developer/CommandLineTools/SDKs/MacOSX10.14.sdk/usr/include/assert.h:44:
    /Library/Developer/CommandLineTools/usr/include/c++/v1/stdlib.h:111:82: error: use of undeclared identifier 'labs'; did you mean 'abs'?
    inline _LIBCPP_INLINE_VISIBILITY long      abs(     long __x) _NOEXCEPT {return  labs(__x);}
                                                                                     ^
    /Library/Developer/CommandLineTools/usr/include/c++/v1/stdlib.h:111:44: note: 'abs' declared here
    inline _LIBCPP_INLINE_VISIBILITY long      abs(     long __x) _NOEXCEPT {return  labs(__x);}
                                               ^
    /Library/Developer/CommandLineTools/usr/include/c++/v1/stdlib.h:113:81: error: use of undeclared identifier 'llabs'
    inline _LIBCPP_INLINE_VISIBILITY long long abs(long long __x) _NOEXCEPT {return llabs(__x);}
                                                                                    ^
    /Library/Developer/CommandLineTools/usr/include/c++/v1/stdlib.h:116:35: error: unknown type name 'ldiv_t'
    inline _LIBCPP_INLINE_VISIBILITY  ldiv_t div(     long __x,      long __y) _NOEXCEPT {return  ldiv(__x, __y);}
                                      ^
    /Library/Developer/CommandLineTools/usr/include/c++/v1/stdlib.h:116:95: error: use of undeclared identifier 'ldiv'; did you mean 'div'?
    inline _LIBCPP_INLINE_VISIBILITY  ldiv_t div(     long __x,      long __y) _NOEXCEPT {return  ldiv(__x, __y);}
                                                                                                  ^
    /Library/Developer/CommandLineTools/usr/include/c++/v1/stdlib.h:116:42: note: 'div' declared here
    inline _LIBCPP_INLINE_VISIBILITY  ldiv_t div(     long __x,      long __y) _NOEXCEPT {return  ldiv(__x, __y);}
                                             ^
    /Library/Developer/CommandLineTools/usr/include/c++/v1/stdlib.h:118:34: error: unknown type name 'lldiv_t'
    inline _LIBCPP_INLINE_VISIBILITY lldiv_t div(long long __x, long long __y) _NOEXCEPT {return lldiv(__x, __y);}
                                     ^
    /Library/Developer/CommandLineTools/usr/include/c++/v1/stdlib.h:118:94: error: use of undeclared identifier 'lldiv'
    inline _LIBCPP_INLINE_VISIBILITY lldiv_t div(long long __x, long long __y) _NOEXCEPT {return lldiv(__x, __y);}
                                                                                                 ^
    In file included from core/desugarer.cpp:19:
    In file included from /Library/Developer/CommandLineTools/usr/include/c++/v1/algorithm:642:
    In file included from /Library/Developer/CommandLineTools/usr/include/c++/v1/cstring:61:
    /Library/Developer/CommandLineTools/usr/include/c++/v1/string.h:74:64: error: use of undeclared identifier 'strchr'
    char* __libcpp_strchr(const char* __s, int __c) {return (char*)strchr(__s, __c);}
                                                                   ^
    /Library/Developer/CommandLineTools/usr/include/c++/v1/string.h:81:75: error: use of undeclared identifier 'strpbrk'
    char* __libcpp_strpbrk(const char* __s1, const char* __s2) {return (char*)strpbrk(__s1, __s2);}
                                                                              ^
    /Library/Developer/CommandLineTools/usr/include/c++/v1/string.h:88:65: error: use of undeclared identifier 'strrchr'; did you mean 'strchr'?
    char* __libcpp_strrchr(const char* __s, int __c) {return (char*)strrchr(__s, __c);}
                                                                    ^
    /Library/Developer/CommandLineTools/usr/include/c++/v1/string.h:76:13: note: 'strchr' declared here
    const char* strchr(const char* __s, int __c) {return __libcpp_strchr(__s, __c);}
                ^
    /Library/Developer/CommandLineTools/usr/include/c++/v1/string.h:95:76: error: use of undeclared identifier 'memchr'
    void* __libcpp_memchr(const void* __s, int __c, size_t __n) {return (void*)memchr(__s, __c, __n);}
                                                                               ^
    /Library/Developer/CommandLineTools/usr/include/c++/v1/string.h:102:74: error: use of undeclared identifier 'strstr'; did you mean 'strchr'?
    char* __libcpp_strstr(const char* __s1, const char* __s2) {return (char*)strstr(__s1, __s2);}
                                                                             ^
    /Library/Developer/CommandLineTools/usr/include/c++/v1/string.h:78:13: note: 'strchr' declared here
          char* strchr(      char* __s, int __c) {return __libcpp_strchr(__s, __c);}
                ^
    /Library/Developer/CommandLineTools/usr/include/c++/v1/string.h:102:74: error: no matching function for call to 'strchr'
    char* __libcpp_strstr(const char* __s1, const char* __s2) {return (char*)strstr(__s1, __s2);}
                                                                             ^
    /Library/Developer/CommandLineTools/usr/include/c++/v1/string.h:78:13: note: candidate disabled: &lt;no message provided&gt;
          char* strchr(      char* __s, int __c) {return __libcpp_strchr(__s, __c);}
                ^
    /Library/Developer/CommandLineTools/usr/include/c++/v1/string.h:102:81: error: cannot initialize a parameter of type 'char *' with an lvalue of type 'const char *'
    char* __libcpp_strstr(const char* __s1, const char* __s2) {return (char*)strstr(__s1, __s2);}
                                                                                    ^~~~
    /Library/Developer/CommandLineTools/usr/include/c++/v1/string.h:78:32: note: passing argument to parameter '__s' here
          char* strchr(      char* __s, int __c) {return __libcpp_strchr(__s, __c);}
                                   ^
    In file included from core/desugarer.cpp:19:
    In file included from /Library/Developer/CommandLineTools/usr/include/c++/v1/algorithm:642:
    /Library/Developer/CommandLineTools/usr/include/c++/v1/cstring:70:9: error: no member named 'memcpy' in the global namespace; did you mean 'memchr'?
    using ::memcpy;
          ~~^
    /Library/Developer/CommandLineTools/usr/include/c++/v1/string.h:97:13: note: 'memchr' declared here
    const void* memchr(const void* __s, int __c, size_t __n) {return __libcpp_memchr(__s, __c, __n);}
                ^
    In file included from core/desugarer.cpp:19:
    In file included from /Library/Developer/CommandLineTools/usr/include/c++/v1/algorithm:642:
    /Library/Developer/CommandLineTools/usr/include/c++/v1/cstring:71:9: error: no member named 'memmove' in the global namespace
    using ::memmove;
          ~~^
    /Library/Developer/CommandLineTools/usr/include/c++/v1/cstring:72:9: error: no member named 'strcpy' in the global namespace; did you mean 'strchr'?
    using ::strcpy;
          ~~^
    /Library/Developer/CommandLineTools/usr/include/c++/v1/string.h:76:13: note: 'strchr' declared here
    const char* strchr(const char* __s, int __c) {return __libcpp_strchr(__s, __c);}
                ^
    In file included from core/desugarer.cpp:19:
    In file included from /Library/Developer/CommandLineTools/usr/include/c++/v1/algorithm:642:
    /Library/Developer/CommandLineTools/usr/include/c++/v1/cstring:73:9: error: no member named 'strncpy' in the global namespace
    using ::strncpy;
          ~~^
    /Library/Developer/CommandLineTools/usr/include/c++/v1/cstring:74:9: error: no member named 'strcat' in the global namespace; did you mean 'strchr'?
    using ::strcat;
          ~~^
    /Library/Developer/CommandLineTools/usr/include/c++/v1/string.h:76:13: note: 'strchr' declared here
    const char* strchr(const char* __s, int __c) {return __libcpp_strchr(__s, __c);}
                ^
    In file included from core/desugarer.cpp:19:
    In file included from /Library/Developer/CommandLineTools/usr/include/c++/v1/algorithm:642:
    /Library/Developer/CommandLineTools/usr/include/c++/v1/cstring:75:9: error: no member named 'strncat' in the global namespace
    using ::strncat;
          ~~^
    fatal error: too many errors emitted, stopping now [-ferror-limit=]
    20 errors generated.
    make: *** [Makefile:118: core/desugarer.o] Error 1
    Traceback (most recent call last):
      File "&lt;string&gt;", line 1, in &lt;module&gt;
      File "/private/var/folders/qf/jkn4v43j08xgst0r9yxyl0dc0000gn/T/pip-install-i4nyb384/jsonnet/setup.py", line 75, in &lt;module&gt;
        test_suite="python._jsonnet_test",
      File "/anaconda3/lib/python3.7/site-packages/setuptools/__init__.py", line 143, in setup
        return distutils.core.setup(**attrs)
      File "/anaconda3/lib/python3.7/distutils/core.py", line 148, in setup
        dist.run_commands()
      File "/anaconda3/lib/python3.7/distutils/dist.py", line 966, in run_commands
        self.run_command(cmd)
      File "/anaconda3/lib/python3.7/distutils/dist.py", line 985, in run_command
        cmd_obj.run()
      File "/anaconda3/lib/python3.7/site-packages/wheel/bdist_wheel.py", line 188, in run
        self.run_command('build')
      File "/anaconda3/lib/python3.7/distutils/cmd.py", line 313, in run_command
        self.distribution.run_command(command)
      File "/anaconda3/lib/python3.7/distutils/dist.py", line 985, in run_command
        cmd_obj.run()
      File "/anaconda3/lib/python3.7/distutils/command/build.py", line 135, in run
        self.run_command(cmd_name)
      File "/anaconda3/lib/python3.7/distutils/cmd.py", line 313, in run_command
        self.distribution.run_command(command)
      File "/anaconda3/lib/python3.7/distutils/dist.py", line 985, in run_command
        cmd_obj.run()
      File "/private/var/folders/qf/jkn4v43j08xgst0r9yxyl0dc0000gn/T/pip-install-i4nyb384/jsonnet/setup.py", line 54, in run
        raise Exception('Could not build %s' % (', '.join(LIB_OBJECTS)))
    Exception: Could not build core/desugarer.o, core/formatter.o, core/libjsonnet.o, core/lexer.o, core/parser.o, core/pass.o, core/static_analysis.o, core/string_utils.o, core/vm.o, third_party/md5/md5.o
  
    ----------------------------------------
    Failed building wheel for jsonnet
    Running setup.py clean for jsonnet
  Failed to build jsonnet
  </code></pre>
  
  <p>My compiler and gcc:</p>
  
  <pre><code>(base) Sakets-MacBook-Pro:usr saketkhandelwal$ gcc -v
  Configured with: --prefix=/Library/Developer/CommandLineTools/usr --with-gxx-include-dir=/usr/include/c++/4.2.1
  Apple LLVM version 10.0.1 (clang-1001.0.46.4)
  Target: x86_64-apple-darwin18.5.0
  Thread model: posix
  InstalledDir: /Library/Developer/CommandLineTools/usr/bin
  (base) Sakets-MacBook-Pro:usr saketkhandelwal$ clang --version
  clang version 4.0.1 (tags/RELEASE_401/final)
  Target: x86_64-apple-darwin18.5.0
  Thread model: posix
  InstalledDir: /anaconda3/bin
  </code></pre>
  
  <p>How do i fix this, i have tried reinstalling command line tools and package headers but still no luck. </p>