command ‘gcc’ failed with exit status 1 error while installing scrapy

When I tried to install Scrapy I got this error:

    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>=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>=1.5.2 in /usr/local/lib/python2.7/site-packages/six-1.6.1-py2.7.egg (from Scrapy)
Downloading/unpacking zope.interface>=3.6.0 (from Twisted>=10.0.0->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>=0.2.1 (from pyOpenSSL->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 "<string>", line 17, in <module>
      File "/tmp/pip_build_root/cryptography/setup.py", line 174, in <module>
        "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 "<string>", line 17, in <module>

  File "/tmp/pip_build_root/cryptography/setup.py", line 174, in <module>

    "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

Solution :

c/_cffi_backend. c:truth:error:ffi. h:No such file or directory
Install the libffi-devel package
yum install libffi-devel


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