我的make.conf

gentoo的make.conf确实是个好东西，保存起来备查。
# These settings were set by the catalyst build script that automatically
# built this stage.
# Please consult /usr/share/portage/config/make.conf.example for a more

# detailed example.

CFLAGS是编译器的编译环境变量，如果为空的话emerge会提示C编译器不能创建可执行文件

CFLAGS="-march=core2 -mtune=generic -O2 -pipe"
CXXFLAGS="${CFLAGS}"
ACCEPT_KEYWORDS="~amd64" 
# WARNING: Changing your CHOST is not something that should be done lightly.
# Please consult http://www.gentoo.org/doc/en/change-chost.xml before changing.
CHOST="x86_64-pc-linux-gnu"
# These are the USE flags that were used in addition to what is provided by the
# profile used for building.
USE=" -qt4 -kde X dbus gtk gnome curl emacs xinerama"
#xinerama作为USE可以让xorg提供扩展屏幕支持
#下面两行是用axel取代emerge自己的fetch功能
FETCHCOMMAND="/usr/bin/axel -a -o \${DISTDIR}/\${FILE} \${URI}"
RESUMECOMMAND=${FETCHCOMMAND}


INPUT_DEVICES="keyboard mouse synaptics"
VIDEO_CARDS="intel"
source /var/lib/layman/make.conf
PORTDIR_OVERLAY="/usr/local/portage"
ACCEPT_LISENSE='google-chrome'
DISTDIR="/var/portage/distfiles"
# Uncomment one or both lines to replace gcc/g++ with clang/clang++ for portage.
#CC="/usr/bin/clang"
#CXX="/usr/bin/clang++"




# Flags for clang without LTO: Insert your arch here instead of k8 and have a look at the manpage of clang for flag descriptions.
# Some gcc flags like -pipe and -pthread also work, though they might be ignored by clang.
#CFLAGS="-march=k8 -O2"




# Flags for clang with LTO:
# If a package does not compile, add it to /etc/portage/package.env like
# app-foo/bar clang
# app-bar/baz clang
# or fallback to gcc!
#RANLIB=':'
#CFLAGS="-march=x86-64 -O4"




# Uncomment to replace gcc with dragonegg; just use all the gcc flags you like and append -fplugin=/path/to/dragonegg.so
#CFLAGS="-march=x86-64 -O2 -fplugin=/usr/lib64/llvm/dragonegg.so"




# Set also CXXFLAGS, mostly the following line suffices, unless you are mixing compilers (e.g. gcc for C, clang++ for C++ programs)
CXXFLAGS="${CFLAGS}"
MAKEOPTS="-j3"




SYNC="rsync://rsync1.at.gentoo.org/gentoo-portage"
RSYNC_TIMEOUT=500
#延长sync的超时时间，在网络状况不好时很有用