title: command 'gcc' failed with exit status 1 error while installing scrapy
body: <p>When I want to install Scrapy I meet this error:</p>
  
  <pre><code>    warning: no previously-included files found matching '*.py'
  Requirement already satisfied (use --upgrade to upgrade): pyOpenSSL in /usr/local/lib/python2.7/site-packages/pyOpenSSL-0.14-py2.7.egg (from Scrapy)
  Requirement already satisfied (use --upgrade to upgrade): cssselect&gt;=0.9 in /usr/local/lib/python2.7/site-packages/cssselect-0.9.1-py2.7.egg (from Scrapy)
  Requirement already satisfied (use --upgrade to upgrade): six&gt;=1.5.2 in /usr/local/lib/python2.7/site-packages/six-1.6.1-py2.7.egg (from Scrapy)
  Downloading/unpacking zope.interface&gt;=3.6.0 (from Twisted&gt;=10.0.0-&gt;Scrapy)
    Downloading zope.interface-4.1.1.tar.gz (864kB): 864kB downloaded
    Running setup.py (path:/tmp/pip_build_root/zope.interface/setup.py) egg_info for package zope.interface
  
      warning: no previously-included files matching '*.dll' found anywhere in distribution
      warning: no previously-included files matching '*.pyc' found anywhere in distribution
      warning: no previously-included files matching '*.pyo' found anywhere in distribution
      warning: no previously-included files matching '*.so' found anywhere in distribution
  Downloading/unpacking cryptography&gt;=0.2.1 (from pyOpenSSL-&gt;Scrapy)
    Downloading cryptography-0.4.tar.gz (260kB): 260kB downloaded
    Running setup.py (path:/tmp/pip_build_root/cryptography/setup.py) egg_info for package cryptography
      Package libffi was not found in the pkg-config search path.
      Perhaps you should add the directory containing `libffi.pc'
      to the PKG_CONFIG_PATH environment variable
      No package 'libffi' found
      Package libffi was not found in the pkg-config search path.
      Perhaps you should add the directory containing `libffi.pc'
      to the PKG_CONFIG_PATH environment variable
      No package 'libffi' found
      Package libffi was not found in the pkg-config search path.
      Perhaps you should add the directory containing `libffi.pc'
      to the PKG_CONFIG_PATH environment variable
      No package 'libffi' found
      Package libffi was not found in the pkg-config search path.
      Perhaps you should add the directory containing `libffi.pc'
      to the PKG_CONFIG_PATH environment variable
      No package 'libffi' found
      Package libffi was not found in the pkg-config search path.
      Perhaps you should add the directory containing `libffi.pc'
      to the PKG_CONFIG_PATH environment variable
      No package 'libffi' found
      c/_cffi_backend.c:14:17: error: ffi.h: No such file or directory
      In file included from c/_cffi_backend.c:21:
      c/malloc_closure.h:33: error: expected specifier-qualifier-list before 'ffi_closure'
      c/malloc_closure.h: In function 'more_core':
      c/malloc_closure.h:69: warning: division by zero
      c/malloc_closure.h:96: error: 'union mmaped_block' has no member named 'next'
      c/malloc_closure.h: At top level:
      c/malloc_closure.h:105: error: expected ')' before '*' token
      c/malloc_closure.h:113: error: expected '=', ',', ';', 'asm' or '__attribute__' before '*' token
      c/_cffi_backend.c:187: error: expected specifier-qualifier-list before 'ffi_cif'
      c/_cffi_backend.c: In function 'cdataowninggc_dealloc':
      c/_cffi_backend.c:1499: error: 'ffi_closure' undeclared (first use in this function)
      c/_cffi_backend.c:1499: error: (Each undeclared identifier is reported only once
      c/_cffi_backend.c:1499: error: for each function it appears in.)
      c/_cffi_backend.c:1499: error: 'closure' undeclared (first use in this function)
      c/_cffi_backend.c:1499: error: expected expression before ')' token
      c/_cffi_backend.c:1502: warning: implicit declaration of function 'cffi_closure_free'
      c/_cffi_backend.c: In function 'cdataowninggc_traverse':
      c/_cffi_backend.c:1514: error: 'ffi_closure' undeclared (first use in this function)
      c/_cffi_backend.c:1514: error: 'closure' undeclared (first use in this function)
      c/_cffi_backend.c:1514: error: expected expression before ')' token
      c/_cffi_backend.c: In function 'cdataowninggc_clear':
      c/_cffi_backend.c:1530: error: 'ffi_closure' undeclared (first use in this function)
      c/_cffi_backend.c:1530: error: 'closure' undeclared (first use in this function)
      c/_cffi_backend.c:1530: error: expected expression before ')' token
      c/_cffi_backend.c: In function 'cdataowning_repr':
      c/_cffi_backend.c:1654: error: 'ffi_closure' undeclared (first use in this function)
      c/_cffi_backend.c:1654: error: expected expression before ')' token
      c/_cffi_backend.c: At top level:
      c/_cffi_backend.c:2200: error: expected declaration specifiers or '...' before 'ffi_abi'
      c/_cffi_backend.c: In function 'cdata_call':
      c/_cffi_backend.c:2334: error: 'ffi_abi' undeclared (first use in this function)
      c/_cffi_backend.c:2334: error: expected ';' before 'fabi'
      c/_cffi_backend.c:2376: error: 'fabi' undeclared (first use in this function)
      c/_cffi_backend.c:2380: error: too many arguments to function 'fb_prepare_cif'
      c/_cffi_backend.c:2385: error: 'cif_description_t' has no member named 'exchange_size'
      c/_cffi_backend.c:2395: error: 'cif_description_t' has no member named 'exchange_offset_arg'
      c/_cffi_backend.c:2425: error: 'cif_description_t' has no member named 'exchange_offset_arg'
      c/_cffi_backend.c:2430: warning: implicit declaration of function 'ffi_call'
      c/_cffi_backend.c:2430: error: 'cif_description_t' has no member named 'cif'
      c/_cffi_backend.c: In function 'b_new_primitive_type':
      c/_cffi_backend.c:3334: error: 'ffi_type' undeclared (first use in this function)
      c/_cffi_backend.c:3334: error: 'ffitype' undeclared (first use in this function)
      c/_cffi_backend.c:3355: error: 'ffi_type_sint8' undeclared (first use in this function)
      c/_cffi_backend.c:3356: error: 'ffi_type_sint16' undeclared (first use in this function)
      c/_cffi_backend.c:3357: error: 'ffi_type_sint32' undeclared (first use in this function)
      c/_cffi_backend.c:3358: error: 'ffi_type_sint64' undeclared (first use in this function)
      c/_cffi_backend.c:3364: error: 'ffi_type_float' undeclared (first use in this function)
      c/_cffi_backend.c:3366: error: 'ffi_type_double' undeclared (first use in this function)
      c/_cffi_backend.c:3368: error: 'ffi_type_longdouble' undeclared (first use in this function)
      c/_cffi_backend.c:3374: error: 'ffi_type_uint8' undeclared (first use in this function)
      c/_cffi_backend.c:3375: error: 'ffi_type_uint16' undeclared (first use in this function)
      c/_cffi_backend.c:3376: error: 'ffi_type_uint32' undeclared (first use in this function)
      c/_cffi_backend.c:3377: error: 'ffi_type_uint64' undeclared (first use in this function)
      c/_cffi_backend.c: At top level:
      c/_cffi_backend.c:3931: error: expected specifier-qualifier-list before 'ffi_type'
      c/_cffi_backend.c:3950: error: expected '=', ',', ';', 'asm' or '__attribute__' before '*' token
      c/_cffi_backend.c: In function 'fb_build':
      c/_cffi_backend.c:4081: error: 'struct funcbuilder_s' has no member named 'atypes'
      c/_cffi_backend.c:4081: error: 'ffi_type' undeclared (first use in this function)
      c/_cffi_backend.c:4081: error: expected expression before ')' token
      c/_cffi_backend.c:4082: error: 'struct funcbuilder_s' has no member named 'nargs'
      c/_cffi_backend.c:4085: error: 'struct funcbuilder_s' has no member named 'rtype'
      c/_cffi_backend.c:4085: warning: implicit declaration of function 'fb_fill_type'
      c/_cffi_backend.c:4093: error: 'cif_description_t' has no member named 'exchange_offset_arg'
      c/_cffi_backend.c:4096: error: 'struct funcbuilder_s' has no member named 'rtype'
      c/_cffi_backend.c:4097: error: 'ffi_arg' undeclared (first use in this function)
      c/_cffi_backend.c:4107: error: 'atype' undeclared (first use in this function)
      c/_cffi_backend.c:4120: error: 'struct funcbuilder_s' has no member named 'atypes'
      c/_cffi_backend.c:4121: error: 'struct funcbuilder_s' has no member named 'atypes'
      c/_cffi_backend.c:4124: error: 'cif_description_t' has no member named 'exchange_offset_arg'
      c/_cffi_backend.c:4131: error: 'cif_description_t' has no member named 'exchange_size'
      c/_cffi_backend.c: In function 'fb_build_name':
      c/_cffi_backend.c:4153: error: 'struct funcbuilder_s' has no member named 'nargs'
      c/_cffi_backend.c:4162: error: 'struct funcbuilder_s' has no member named 'fct'
      c/_cffi_backend.c:4164: error: 'struct funcbuilder_s' has no member named 'fct'
      c/_cffi_backend.c: In function 'fb_prepare_ctype':
      c/_cffi_backend.c:4205: error: 'struct funcbuilder_s' has no member named 'fct'
      c/_cffi_backend.c:4215: error: 'struct funcbuilder_s' has no member named 'fct'
      c/_cffi_backend.c: At top level:
      c/_cffi_backend.c:4235: error: expected declaration specifiers or '...' before 'ffi_abi'
      c/_cffi_backend.c: In function 'fb_prepare_cif':
      c/_cffi_backend.c:4262: warning: implicit declaration of function 'ffi_prep_cif'
      c/_cffi_backend.c:4262: error: 'cif_description_t' has no member named 'cif'
      c/_cffi_backend.c:4262: error: 'fabi' undeclared (first use in this function)
      c/_cffi_backend.c:4262: error: 'struct funcbuilder_s' has no member named 'nargs'
      c/_cffi_backend.c:4263: error: 'struct funcbuilder_s' has no member named 'rtype'
      c/_cffi_backend.c:4263: error: 'struct funcbuilder_s' has no member named 'atypes'
      c/_cffi_backend.c:4263: error: 'FFI_OK' undeclared (first use in this function)
      c/_cffi_backend.c: In function 'b_new_function_type':
      c/_cffi_backend.c:4280: error: 'FFI_DEFAULT_ABI' undeclared (first use in this function)
      c/_cffi_backend.c:4318: error: too many arguments to function 'fb_prepare_cif'
      c/_cffi_backend.c:4326: error: 'struct funcbuilder_s' has no member named 'nargs'
      c/_cffi_backend.c:4336: error: 'struct funcbuilder_s' has no member named 'nargs'
      c/_cffi_backend.c: In function 'convert_from_object_fficallback':
      c/_cffi_backend.c:4360: error: 'ffi_arg' undeclared (first use in this function)
      c/_cffi_backend.c: At top level:
      c/_cffi_backend.c:4432: error: expected ')' before '*' token
      c/_cffi_backend.c: In function 'b_callback':
      c/_cffi_backend.c:4503: error: 'ffi_closure' undeclared (first use in this function)
      c/_cffi_backend.c:4503: error: 'closure' undeclared (first use in this function)
      c/_cffi_backend.c:4524: error: 'ffi_arg' undeclared (first use in this function)
      c/_cffi_backend.c:4542: warning: implicit declaration of function 'cffi_closure_alloc'
      c/_cffi_backend.c:4559: warning: implicit declaration of function 'ffi_prep_closure'
      c/_cffi_backend.c:4559: error: 'cif_description_t' has no member named 'cif'
      c/_cffi_backend.c:4560: error: 'invoke_callback' undeclared (first use in this function)
      c/_cffi_backend.c:4560: error: 'FFI_OK' undeclared (first use in this function)
      c/_cffi_backend.c: In function 'init_cffi_backend':
      c/_cffi_backend.c:5489: error: 'FFI_DEFAULT_ABI' undeclared (first use in this function)
      Traceback (most recent call last):
        File "&lt;string&gt;", line 17, in &lt;module&gt;
        File "/tmp/pip_build_root/cryptography/setup.py", line 174, in &lt;module&gt;
          "test": PyTest,
        File "/usr/local/lib/python2.7/distutils/core.py", line 112, in setup
          _setup_distribution = dist = klass(attrs)
        File "build/bdist.linux-x86_64/egg/setuptools/dist.py", line 260, in __init__
        File "build/bdist.linux-x86_64/egg/setuptools/dist.py", line 285, in fetch_build_eggs
        File "build/bdist.linux-x86_64/egg/pkg_resources.py", line 631, in resolve
        File "build/bdist.linux-x86_64/egg/pkg_resources.py", line 871, in best_match
        File "build/bdist.linux-x86_64/egg/pkg_resources.py", line 883, in obtain
        File "build/bdist.linux-x86_64/egg/setuptools/dist.py", line 335, in fetch_build_egg
        File "build/bdist.linux-x86_64/egg/setuptools/command/easy_install.py", line 595, in easy_install
        File "build/bdist.linux-x86_64/egg/setuptools/command/easy_install.py", line 625, in install_item
        File "build/bdist.linux-x86_64/egg/setuptools/command/easy_install.py", line 822, in install_eggs
        File "build/bdist.linux-x86_64/egg/setuptools/command/easy_install.py", line 1028, in build_and_install
        File "build/bdist.linux-x86_64/egg/setuptools/command/easy_install.py", line 1016, in run_setup
      distutils.errors.DistutilsError: Setup script exited with error: command 'gcc' failed with exit status 1
      Complete output from command python setup.py egg_info:
      Package libffi was not found in the pkg-config search path.
  
  Perhaps you should add the directory containing `libffi.pc'
  
  to the PKG_CONFIG_PATH environment variable
  
  No package 'libffi' found
  
  Package libffi was not found in the pkg-config search path.
  
  Perhaps you should add the directory containing `libffi.pc'
  
  to the PKG_CONFIG_PATH environment variable
  
  No package 'libffi' found
  
  Package libffi was not found in the pkg-config search path.
  
  Perhaps you should add the directory containing `libffi.pc'
  
  to the PKG_CONFIG_PATH environment variable
  
  No package 'libffi' found
  
  Package libffi was not found in the pkg-config search path.
  
  Perhaps you should add the directory containing `libffi.pc'
  
  to the PKG_CONFIG_PATH environment variable
  
  No package 'libffi' found
  
  Package libffi was not found in the pkg-config search path.
  
  Perhaps you should add the directory containing `libffi.pc'
  
  to the PKG_CONFIG_PATH environment variable
  
  No package 'libffi' found
  
  c/_cffi_backend.c:14:17: error: ffi.h: No such file or directory
  
  In file included from c/_cffi_backend.c:21:
  
  c/malloc_closure.h:33: error: expected specifier-qualifier-list before 'ffi_closure'
  
  c/malloc_closure.h: In function 'more_core':
  
  c/malloc_closure.h:69: warning: division by zero
  
  c/malloc_closure.h:96: error: 'union mmaped_block' has no member named 'next'
  
  c/malloc_closure.h: At top level:
  
  c/malloc_closure.h:105: error: expected ')' before '*' token
  
  c/malloc_closure.h:113: error: expected '=', ',', ';', 'asm' or '__attribute__' before '*' token
  
  c/_cffi_backend.c:187: error: expected specifier-qualifier-list before 'ffi_cif'
  
  c/_cffi_backend.c: In function 'cdataowninggc_dealloc':
  
  c/_cffi_backend.c:1499: error: 'ffi_closure' undeclared (first use in this function)
  
  c/_cffi_backend.c:1499: error: (Each undeclared identifier is reported only once
  
  c/_cffi_backend.c:1499: error: for each function it appears in.)
  
  c/_cffi_backend.c:1499: error: 'closure' undeclared (first use in this function)
  
  c/_cffi_backend.c:1499: error: expected expression before ')' token
  
  c/_cffi_backend.c:1502: warning: implicit declaration of function 'cffi_closure_free'
  
  c/_cffi_backend.c: In function 'cdataowninggc_traverse':
  
  c/_cffi_backend.c:1514: error: 'ffi_closure' undeclared (first use in this function)
  
  c/_cffi_backend.c:1514: error: 'closure' undeclared (first use in this function)
  
  c/_cffi_backend.c:1514: error: expected expression before ')' token
  
  c/_cffi_backend.c: In function 'cdataowninggc_clear':
  
  c/_cffi_backend.c:1530: error: 'ffi_closure' undeclared (first use in this function)
  
  c/_cffi_backend.c:1530: error: 'closure' undeclared (first use in this function)
  
  c/_cffi_backend.c:1530: error: expected expression before ')' token
  
  c/_cffi_backend.c: In function 'cdataowning_repr':
  
  c/_cffi_backend.c:1654: error: 'ffi_closure' undeclared (first use in this function)
  
  c/_cffi_backend.c:1654: error: expected expression before ')' token
  
  c/_cffi_backend.c: At top level:
  
  c/_cffi_backend.c:2200: error: expected declaration specifiers or '...' before 'ffi_abi'
  
  c/_cffi_backend.c: In function 'cdata_call':
  
  c/_cffi_backend.c:2334: error: 'ffi_abi' undeclared (first use in this function)
  
  c/_cffi_backend.c:2334: error: expected ';' before 'fabi'
  
  c/_cffi_backend.c:2376: error: 'fabi' undeclared (first use in this function)
  
  c/_cffi_backend.c:2380: error: too many arguments to function 'fb_prepare_cif'
  
  c/_cffi_backend.c:2385: error: 'cif_description_t' has no member named 'exchange_size'
  
  c/_cffi_backend.c:2395: error: 'cif_description_t' has no member named 'exchange_offset_arg'
  
  c/_cffi_backend.c:2425: error: 'cif_description_t' has no member named 'exchange_offset_arg'
  
  c/_cffi_backend.c:2430: warning: implicit declaration of function 'ffi_call'
  
  c/_cffi_backend.c:2430: error: 'cif_description_t' has no member named 'cif'
  
  c/_cffi_backend.c: In function 'b_new_primitive_type':
  
  c/_cffi_backend.c:3334: error: 'ffi_type' undeclared (first use in this function)
  
  c/_cffi_backend.c:3334: error: 'ffitype' undeclared (first use in this function)
  
  c/_cffi_backend.c:3355: error: 'ffi_type_sint8' undeclared (first use in this function)
  
  c/_cffi_backend.c:3356: error: 'ffi_type_sint16' undeclared (first use in this function)
  
  c/_cffi_backend.c:3357: error: 'ffi_type_sint32' undeclared (first use in this function)
  
  c/_cffi_backend.c:3358: error: 'ffi_type_sint64' undeclared (first use in this function)
  
  c/_cffi_backend.c:3364: error: 'ffi_type_float' undeclared (first use in this function)
  
  c/_cffi_backend.c:3366: error: 'ffi_type_double' undeclared (first use in this function)
  
  c/_cffi_backend.c:3368: error: 'ffi_type_longdouble' undeclared (first use in this function)
  
  c/_cffi_backend.c:3374: error: 'ffi_type_uint8' undeclared (first use in this function)
  
  c/_cffi_backend.c:3375: error: 'ffi_type_uint16' undeclared (first use in this function)
  
  c/_cffi_backend.c:3376: error: 'ffi_type_uint32' undeclared (first use in this function)
  
  c/_cffi_backend.c:3377: error: 'ffi_type_uint64' undeclared (first use in this function)
  
  c/_cffi_backend.c: At top level:
  
  c/_cffi_backend.c:3931: error: expected specifier-qualifier-list before 'ffi_type'
  
  c/_cffi_backend.c:3950: error: expected '=', ',', ';', 'asm' or '__attribute__' before '*' token
  
  c/_cffi_backend.c: In function 'fb_build':
  
  c/_cffi_backend.c:4081: error: 'struct funcbuilder_s' has no member named 'atypes'
  
  c/_cffi_backend.c:4081: error: 'ffi_type' undeclared (first use in this function)
  
  c/_cffi_backend.c:4081: error: expected expression before ')' token
  
  c/_cffi_backend.c:4082: error: 'struct funcbuilder_s' has no member named 'nargs'
  
  c/_cffi_backend.c:4085: error: 'struct funcbuilder_s' has no member named 'rtype'
  
  c/_cffi_backend.c:4085: warning: implicit declaration of function 'fb_fill_type'
  
  c/_cffi_backend.c:4093: error: 'cif_description_t' has no member named 'exchange_offset_arg'
  
  c/_cffi_backend.c:4096: error: 'struct funcbuilder_s' has no member named 'rtype'
  
  c/_cffi_backend.c:4097: error: 'ffi_arg' undeclared (first use in this function)
  
  c/_cffi_backend.c:4107: error: 'atype' undeclared (first use in this function)
  
  c/_cffi_backend.c:4120: error: 'struct funcbuilder_s' has no member named 'atypes'
  
  c/_cffi_backend.c:4121: error: 'struct funcbuilder_s' has no member named 'atypes'
  
  c/_cffi_backend.c:4124: error: 'cif_description_t' has no member named 'exchange_offset_arg'
  
  c/_cffi_backend.c:4131: error: 'cif_description_t' has no member named 'exchange_size'
  
  c/_cffi_backend.c: In function 'fb_build_name':
  
  c/_cffi_backend.c:4153: error: 'struct funcbuilder_s' has no member named 'nargs'
  
  c/_cffi_backend.c:4162: error: 'struct funcbuilder_s' has no member named 'fct'
  
  c/_cffi_backend.c:4164: error: 'struct funcbuilder_s' has no member named 'fct'
  
  c/_cffi_backend.c: In function 'fb_prepare_ctype':
  
  c/_cffi_backend.c:4205: error: 'struct funcbuilder_s' has no member named 'fct'
  
  c/_cffi_backend.c:4215: error: 'struct funcbuilder_s' has no member named 'fct'
  
  c/_cffi_backend.c: At top level:
  
  c/_cffi_backend.c:4235: error: expected declaration specifiers or '...' before 'ffi_abi'
  
  c/_cffi_backend.c: In function 'fb_prepare_cif':
  
  c/_cffi_backend.c:4262: warning: implicit declaration of function 'ffi_prep_cif'
  
  c/_cffi_backend.c:4262: error: 'cif_description_t' has no member named 'cif'
  
  c/_cffi_backend.c:4262: error: 'fabi' undeclared (first use in this function)
  
  c/_cffi_backend.c:4262: error: 'struct funcbuilder_s' has no member named 'nargs'
  
  c/_cffi_backend.c:4263: error: 'struct funcbuilder_s' has no member named 'rtype'
  
  c/_cffi_backend.c:4263: error: 'struct funcbuilder_s' has no member named 'atypes'
  
  c/_cffi_backend.c:4263: error: 'FFI_OK' undeclared (first use in this function)
  
  c/_cffi_backend.c: In function 'b_new_function_type':
  
  c/_cffi_backend.c:4280: error: 'FFI_DEFAULT_ABI' undeclared (first use in this function)
  
  c/_cffi_backend.c:4318: error: too many arguments to function 'fb_prepare_cif'
  
  c/_cffi_backend.c:4326: error: 'struct funcbuilder_s' has no member named 'nargs'
  
  c/_cffi_backend.c:4336: error: 'struct funcbuilder_s' has no member named 'nargs'
  
  c/_cffi_backend.c: In function 'convert_from_object_fficallback':
  
  c/_cffi_backend.c:4360: error: 'ffi_arg' undeclared (first use in this function)
  
  c/_cffi_backend.c: At top level:
  
  c/_cffi_backend.c:4432: error: expected ')' before '*' token
  
  c/_cffi_backend.c: In function 'b_callback':
  
  c/_cffi_backend.c:4503: error: 'ffi_closure' undeclared (first use in this function)
  
  c/_cffi_backend.c:4503: error: 'closure' undeclared (first use in this function)
  
  c/_cffi_backend.c:4524: error: 'ffi_arg' undeclared (first use in this function)
  
  c/_cffi_backend.c:4542: warning: implicit declaration of function 'cffi_closure_alloc'
  
  c/_cffi_backend.c:4559: warning: implicit declaration of function 'ffi_prep_closure'
  
  c/_cffi_backend.c:4559: error: 'cif_description_t' has no member named 'cif'
  
  c/_cffi_backend.c:4560: error: 'invoke_callback' undeclared (first use in this function)
  
  c/_cffi_backend.c:4560: error: 'FFI_OK' undeclared (first use in this function)
  
  c/_cffi_backend.c: In function 'init_cffi_backend':
  
  c/_cffi_backend.c:5489: error: 'FFI_DEFAULT_ABI' undeclared (first use in this function)
  
  Traceback (most recent call last):
  
    File "&lt;string&gt;", line 17, in &lt;module&gt;
  
    File "/tmp/pip_build_root/cryptography/setup.py", line 174, in &lt;module&gt;
  
      "test": PyTest,
  
    File "/usr/local/lib/python2.7/distutils/core.py", line 112, in setup
  
      _setup_distribution = dist = klass(attrs)
  
    File "build/bdist.linux-x86_64/egg/setuptools/dist.py", line 260, in __init__
  
    File "build/bdist.linux-x86_64/egg/setuptools/dist.py", line 285, in fetch_build_eggs
  
    File "build/bdist.linux-x86_64/egg/pkg_resources.py", line 631, in resolve
  
    File "build/bdist.linux-x86_64/egg/pkg_resources.py", line 871, in best_match
  
    File "build/bdist.linux-x86_64/egg/pkg_resources.py", line 883, in obtain
  
    File "build/bdist.linux-x86_64/egg/setuptools/dist.py", line 335, in fetch_build_egg
  
    File "build/bdist.linux-x86_64/egg/setuptools/command/easy_install.py", line 595, in easy_install
  
    File "build/bdist.linux-x86_64/egg/setuptools/command/easy_install.py", line 625, in install_item
  
    File "build/bdist.linux-x86_64/egg/setuptools/command/easy_install.py", line 822, in install_eggs
  
    File "build/bdist.linux-x86_64/egg/setuptools/command/easy_install.py", line 1028, in build_and_install
  
    File "build/bdist.linux-x86_64/egg/setuptools/command/easy_install.py", line 1016, in run_setup
  
  distutils.errors.DistutilsError: Setup script exited with error: command 'gcc' failed with exit status 1
  
  ----------------------------------------
  Cleaning up...
  Command python setup.py egg_info failed with error code 1 in /tmp/pip_build_root/cryptography
  Storing debug log for failure in /root/.pip/pip.log
  </code></pre>
  
  <p>I tried this answer but failed also，<a href="https://stackoverflow.com/questions/10927492/getting-gcc-failed-error-while-installing-scrapy">Getting gcc failed error while installing scrapy</a>,  would any one tell me how to correct it?</p>
  
  <p>PS: My OS is centos 6.5 </p>