# emerge -a --oneshot gcc

These are the packages that would be merged, in order:

Calculating dependencies... done!
[ebuild  N     ] sys-libs/libraw1394-2.1.0-r1  USE="-static-libs" ABI_X86="32 (64) (-x32)"
[ebuild  N    #] gnome-base/gnome-common-3.12.0
[ebuild     U ~] virtual/acl-0-r2 [0-r1] ABI_X86="32%* (64%*) (-x32)"
[ebuild  NS    ] media-libs/tiff-3.9.7-r1 [4.0.3-r6] USE="cxx jpeg zlib -jbig" ABI_X86="32 (64) (-x32)"
[ebuild  N    ~] dev-libs/libnl-3.2.25  USE="-python -static-libs -utils" ABI_X86="32 (64) (-x32)" PYTHON_TARGETS="python2_7 python3_3 (-python3_2) -python3_4"
[ebuild     U ~] media-libs/giflib-4.2.3-r1 [4.1.6-r3]
[ebuild  NS    ] dev-libs/openssl-0.9.8z_p3 [1.0.1j] USE="(sse2) zlib -bindist -gmp -kerberos {-test}" ABI_X86="32 (64) (-x32)"
[ebuild     U ~] dev-libs/libgcrypt-1.6.2 [1.5.4-r1]
[ebuild  NS   ~] media-libs/lcms-1.19-r3 [2.6-r1] USE="jpeg tiff zlib -python -static-libs" ABI_X86="32 (64) (-x32)" PYTHON_TARGETS="python2_7 python3_3 (-python3_2) -python3_4"
[ebuild  N     ] dev-libs/udis86-1.7-r2  USE="{-test}" ABI_X86="32 (64) (-x32)"
[ebuild  NS   ~] dev-libs/libgcrypt-1.5.4-r100 [1.5.4-r1] ABI_X86="32 (64) (-x32)"
[ebuild  N     ] media-libs/libart_lgpl-2.3.21-r2  ABI_X86="32 (64) (-x32)"
[ebuild  N     ] x11-libs/libXxf86dga-1.1.4  USE="-static-libs" ABI_X86="32 (64) (-x32)"
[ebuild  N     ] sys-libs/libavc1394-0.5.4-r1  USE="-static-libs" ABI_X86="32 (64) (-x32)"
[ebuild  N    ~] net-libs/libtirpc-0.2.5  USE="-ipv6 -kerberos -static-libs" ABI_X86="32 (64) (-x32)"
[ebuild  N     ] x11-libs/libXvMC-1.0.8  USE="-static-libs" ABI_X86="32 (64) (-x32)"
[ebuild  N     ] app-admin/eselect-xvmc-0.4
[ebuild  N     ] sys-libs/slang-2.2.4-r1  USE="pcre png readline zlib -cjk -static-libs" ABI_X86="32 (64) (-x32)"
[ebuild  N    #] gnome-base/gnome-mime-data-2.18.0  USE="-debug"
[ebuild  N    ~] media-libs/imlib-1.9.15-r4  USE="-doc -static-libs" ABI_X86="32 (64) (-x32)"
[ebuild  N    #] app-emulation/emul-linux-x86-xlibs-20140508  USE="(development) opengl" ABI_X86="32"
[ebuild  N     ] x11-libs/pangox-compat-0.0.2-r1  ABI_X86="32 (64) (-x32)"
[ebuild  N     ] media-libs/glew-1.10.0-r2  USE="-doc -static-libs" ABI_X86="32 (64) (-x32)"
[ebuild  N    #] app-emulation/emul-linux-x86-opengl-20140508  USE="development" ABI_X86="32"
[ebuild  N    #] gnome-base/libglade-2.6.4-r2  USE="-static-libs {-test} -tools" ABI_X86="32 (64) (-x32)" PYTHON_SINGLE_TARGET="python2_7 (-pypy)" PYTHON_TARGETS="python2_7 (-pypy)"
[ebuild  N    #] gnome-base/gconf-3.2.6-r3  USE="introspection ldap (policykit) -debug" ABI_X86="32 (64) (-x32)" PYTHON_TARGETS="python2_7"
[ebuild  N    #] gnome-base/gnome-vfs-2.24.4-r2  USE="acl fam samba ssl -avahi -doc -gnutls -ipv6 -kerberos {-test}" ABI_X86="32 (64) (-x32)"
[ebuild  N     ] net-libs/libproxy-0.4.11-r2  USE="kde -gnome -mono -networkmanager -perl -python -spidermonkey {-test} -webkit" ABI_X86="32 (64) (-x32)" PYTHON_TARGETS="python2_7"
[ebuild  N     ] net-libs/glib-networking-2.40.1-r1  USE="libproxy ssl -gnome -smartcard {-test}" ABI_X86="32 (64) (-x32)"
[ebuild  N     ] net-libs/libsoup-2.46.0-r1  USE="introspection samba ssl -debug {-test}" ABI_X86="32 (64) (-x32)"
[ebuild  N    #] app-emulation/emul-linux-x86-baselibs-20140508-r12  USE="development (-kerberos) (-ldap) (-pam)" ABI_X86="32"
[ebuild  N    #] app-emulation/emul-linux-x86-gtklibs-20140508-r3  USE="development" ABI_X86="32"
[ebuild   R    ] sys-devel/gcc-4.8.3  USE="awt* gcj*"
[blocks B      ] <=app-emulation/emul-linux-x86-baselibs-20140508-r13 ("<=app-emulation/emul-linux-x86-baselibs-20140508-r13" is blocking net-misc/curl-7.39.0)
[blocks B      ] dev-libs/libgcrypt:0/11 ("dev-libs/libgcrypt:0/11" is blocking dev-libs/libgcrypt-1.5.4-r100)
[blocks B      ] <=app-emulation/emul-linux-x86-baselibs-20140508-r12 ("<=app-emulation/emul-linux-x86-baselibs-20140508-r12" is blocking dev-libs/nspr-4.10.6-r1, dev-libs/nss-3.16.5)

!!! Multiple package instances within a single package slot have been pulled
!!! into the dependency graph, resulting in a slot conflict:

dev-libs/libgcrypt:0

  (dev-libs/libgcrypt-1.5.4-r1::gentoo, installed) pulled in by
    dev-libs/libgcrypt:0/11= required by (www-client/chromium-38.0.2125.101::gentoo, installed)
    >=dev-libs/libgcrypt-1.5.3:0/11=[abi_x86_32(-),abi_x86_64(-)] required by (dev-libs/libxslt-1.1.28-r4::gentoo, installed)
    (and 2 more with the same problems)

  (dev-libs/libgcrypt-1.6.2::gentoo, ebuild scheduled for merge) pulled in by
    >=dev-libs/libgcrypt-1.6.1-r1:0[abi_x86_32(-)] required by (app-emulation/emul-linux-x86-baselibs-20140508-r12::gentoo, ebuild scheduled for merge)


It may be possible to solve this problem by using package.mask to
prevent one of those packages from being selected. However, it is also
possible that conflicting dependencies exist such that they are
impossible to satisfy simultaneously.  If such a conflict exists in
the dependencies of two different packages, then those packages can
not be installed simultaneously. You may want to try a larger value of
the --backtrack option, such as --backtrack=30, in order to see if
that will solve this conflict automatically.

For more information, see MASKED PACKAGES section in the emerge man
page or refer to the Gentoo Handbook.


 * Error: The above package list contains packages which cannot be
 * installed at the same time on the same system.

  (app-emulation/emul-linux-x86-baselibs-20140508-r12::gentoo, ebuild scheduled for merge) pulled in by
    ~app-emulation/emul-linux-x86-baselibs-20140508 required by (app-emulation/emul-linux-x86-gtklibs-20140508-r3::gentoo, ebuild scheduled for merge)
    app-emulation/emul-linux-x86-baselibs required by (app-emulation/wine-1.7.19-r1::gentoo, installed)

  (net-misc/curl-7.39.0::gentoo, installed) pulled in by
    >=net-misc/curl-7.18.2 required by (media-libs/libquvi-0.4.1-r1::gentoo, installed)
    net-misc/curl required by (dev-cpp/libcmis-0.4.1::gentoo, installed)
    net-misc/curl required by (dev-vcs/git-2.0.4::gentoo, installed)
    >=net-misc/curl-7.10 required by (app-crypt/gnupg-2.0.26::gentoo, installed)
    net-misc/curl required by (media-libs/raptor-2.0.9::gentoo, installed)
    >=net-misc/curl-7.21.4 required by (app-office/libreoffice-bin-4.2.6.3-r2::gentoo, installed)
    >=net-misc/curl-7.20.0-r1[ssl] required by (dev-util/cmake-2.8.12.2-r1::gentoo, installed)
    net-misc/curl required by (app-emulation/virtualbox-4.2.24::gentoo, installed)

  (dev-libs/nss-3.16.5::gentoo, installed) pulled in by
    >=dev-libs/nss-3.16.2 required by (mail-client/thunderbird-24.8.0::gentoo, installed)
    dev-libs/nss required by (www-plugins/adobe-flash-11.2.202.418::gentoo, installed)
    >=dev-libs/nss-3.14.3:= required by (www-client/chromium-38.0.2125.101::gentoo, installed)
    >=dev-libs/nss-3.16.2 required by (www-client/firefox-24.8.0::gentoo, installed)
    >=dev-libs/nss-3.12.5-r1 required by (dev-java/icedtea-6.1.13.5-r1::gentoo, installed)
    >=dev-libs/nss-3.12.9 required by (app-office/libreoffice-bin-4.2.6.3-r2::gentoo, installed)
    >=dev-libs/nss-3.14.3:0/0= required by (www-client/chromium-38.0.2125.101::gentoo, installed)
    >=dev-libs/nss-3.12.5-r1 required by (dev-java/icedtea-7.2.5.3::gentoo, installed)
    >=dev-libs/nss-3.15.4[abi_x86_32(-)] required by (www-plugins/adobe-flash-11.2.202.418::gentoo, installed)

  (dev-libs/nspr-4.10.6-r1::gentoo, installed) pulled in by
    dev-libs/nspr required by (www-plugins/adobe-flash-11.2.202.418::gentoo, installed)
    >=dev-libs/nspr-4.10.4 required by (www-client/firefox-24.8.0::gentoo, installed)
    dev-libs/nspr:0/0= required by (www-client/chromium-38.0.2125.101::gentoo, installed)
    >=dev-libs/nspr-4.9.4 required by (dev-lang/spidermonkey-17.0.0-r3::gentoo, installed)
    >=dev-libs/nspr-4.10.4[abi_x86_32(-)] required by (www-plugins/adobe-flash-11.2.202.418::gentoo, installed)
    >=dev-libs/nspr-4.10.4 required by (mail-client/thunderbird-24.8.0::gentoo, installed)
    >=dev-libs/nspr-4.8.8 required by (app-office/libreoffice-bin-4.2.6.3-r2::gentoo, installed)
    dev-libs/nspr:= required by (www-client/chromium-38.0.2125.101::gentoo, installed)
    >=dev-libs/nspr-4.10.6-r1[abi_x86_32(-)?,abi_x86_64(-)?,abi_x86_x32(-)?,abi_mips_n32(-)?,abi_mips_n64(-)?,abi_mips_o32(-)?,abi_ppc_32(-)?,abi_ppc_64(-)?,abi_s390_32(-)?,abi_s390_64(-)?] (>=dev-libs/nspr-4.10.6-r1[abi_x86_32(-),abi_x86_64(-)]) required by (dev-libs/nss-3.16.5::gentoo, installed)


For more information about Blocked Packages, please refer to the following
section of the Gentoo Linux x86 Handbook (architecture is irrelevant):

http://www.gentoo.org/doc/en/handbook/handbook-x86.xml?full=1#blocked


The following keyword changes are necessary to proceed:
 (see "package.accept_keywords" in the portage(5) man page for more details)
# required by app-emulation/emul-linux-x86-gtklibs-20140508-r3[abi_x86_32]
# required by sys-devel/gcc-4.8.3[gcj,awt]
# required by gcc (argument)
=media-libs/imlib-1.9.15-r4 ~amd64
# required by app-emulation/emul-linux-x86-baselibs-20140508-r12[abi_x86_32]
# required by app-emulation/emul-linux-x86-gtklibs-20140508-r3
# required by sys-devel/gcc-4.8.3[gcj,awt]
# required by gcc (argument)
=media-libs/lcms-1.19-r3 ~amd64
# required by app-emulation/emul-linux-x86-baselibs-20140508-r12[abi_x86_32]
# required by app-emulation/emul-linux-x86-gtklibs-20140508-r3
# required by sys-devel/gcc-4.8.3[gcj,awt]
# required by gcc (argument)
=dev-libs/libnl-3.2.25 ~amd64
# required by app-emulation/emul-linux-x86-baselibs-20140508-r12[abi_x86_32]
# required by app-emulation/emul-linux-x86-gtklibs-20140508-r3
# required by sys-devel/gcc-4.8.3[gcj,awt]
# required by gcc (argument)
=dev-libs/libgcrypt-1.5.4-r100 ~amd64
# required by media-video/vlc-2.1.2[gcrypt]
# required by media-libs/phonon-vlc-0.7.2
# required by media-libs/phonon-4.7.2[vlc]
# required by kde-base/phonon-kde-4.12.5
# required by kde-base/kdebase-meta-4.12.5
# required by @selected
# required by @world (argument)
=dev-libs/libgcrypt-1.6.2 ~amd64
# required by dev-java/icedtea-7.2.5.3
# required by @selected
# required by @world (argument)
=media-libs/giflib-4.2.3-r1 ~amd64
# required by app-emulation/emul-linux-x86-baselibs-20140508-r12[abi_x86_32]
# required by app-emulation/emul-linux-x86-gtklibs-20140508-r3
# required by sys-devel/gcc-4.8.3[gcj,awt]
# required by gcc (argument)
=net-libs/libtirpc-0.2.5 ~amd64
# required by app-arch/libarchive-3.1.2-r1[acl]
# required by kde-base/ark-4.12.5
# required by kde-base/kdeutils-meta-4.12.5
# required by @selected
# required by @world (argument)
=virtual/acl-0-r2 ~amd64

The following mask changes are necessary to proceed:
 (see "package.unmask" in the portage(5) man page for more details)
# required by app-emulation/emul-linux-x86-gtklibs-20140508-r3
# required by sys-devel/gcc-4.8.3[gcj,awt]
# required by gcc (argument)
# /etc/portage/package.mask:
=app-emulation/emul-linux-x86-xlibs-20140508
# required by gnome-base/gnome-vfs-2.24.4-r2
# required by app-emulation/emul-linux-x86-gtklibs-20140508-r3[abi_x86_32]
# required by sys-devel/gcc-4.8.3[gcj,awt]
# required by gcc (argument)
# /etc/portage/package.mask:
=gnome-base/gnome-common-3.12.0
# required by app-emulation/emul-linux-x86-gtklibs-20140508-r3
# required by sys-devel/gcc-4.8.3[gcj,awt]
# required by gcc (argument)
# /etc/portage/package.mask:
=app-emulation/emul-linux-x86-baselibs-20140508-r12
# required by app-emulation/emul-linux-x86-gtklibs-20140508-r3
# required by sys-devel/gcc-4.8.3[gcj,awt]
# required by gcc (argument)
# /etc/portage/package.mask:
=app-emulation/emul-linux-x86-opengl-20140508
# required by app-emulation/emul-linux-x86-gtklibs-20140508-r3[abi_x86_32]
# required by sys-devel/gcc-4.8.3[gcj,awt]
# required by gcc (argument)
# /etc/portage/package.mask:
=gnome-base/libglade-2.6.4-r2
# required by app-emulation/emul-linux-x86-gtklibs-20140508-r3[abi_x86_32]
# required by sys-devel/gcc-4.8.3[gcj,awt]
# required by gcc (argument)
# /etc/portage/package.mask:
=gnome-base/gconf-3.2.6-r3
# required by gnome-base/gnome-vfs-2.24.4-r2
# required by app-emulation/emul-linux-x86-gtklibs-20140508-r3[abi_x86_32]
# required by sys-devel/gcc-4.8.3[gcj,awt]
# required by gcc (argument)
# /etc/portage/package.mask:
=gnome-base/gnome-mime-data-2.18.0
# required by sys-devel/gcc-4.8.3[gcj,awt]
# required by gcc (argument)
# /etc/portage/package.mask:
=app-emulation/emul-linux-x86-gtklibs-20140508-r3
# required by app-emulation/emul-linux-x86-gtklibs-20140508-r3[abi_x86_32]
# required by sys-devel/gcc-4.8.3[gcj,awt]
# required by gcc (argument)
# /etc/portage/package.mask:
=gnome-base/gnome-vfs-2.24.4-r2

NOTE: The --autounmask-keep-masks option will prevent emerge
      from creating package.unmask or ** keyword changes.

Use --autounmask-write to write changes to config files (honoring
CONFIG_PROTECT). Carefully examine the list of proposed changes,
paying special attention to mask or keyword changes that may expose
experimental or unstable packages.