过去一切都很好，但是现在，在我将Macbook升级为Mavericks，R升级到3.0.2后，我还必须升级languageR和lme4包，现在languageR为1.4，lme4为1.0.4。
问题是我总是遇到这个错误：
> pvals.fnc(mod1)
the input model is not a mer object
NULL
有人建议使用其他方法来计算p值（lme4 and languageR compatibility error: "input model is not a mer object”）。但我不仅需要p值，还需要pvals.fnc可以返回的其他参数。有人建议将lme4降级为'0.999999.2'（LMERConvenienceFunctions error on back and forward fitting functions: model not a mer object），但不幸的是我无法在小牛队中安装'0.999999.2'。它显示以下错误：
installing *source* package ‘lme4’ ...
package ‘lme4’ successfully unpacked and MD5 sums checked
libs Library/Frameworks/R.framework/Resources/share/make/shlib.mk:6: warning: overriding commands for target `lme4.so'
Makevars:7: warning: ignoring old commands for target `lme4.so'
llvm-gcc-4.2 -arch x86_64 -std=gnu99 -I/Library/Frameworks/R.framework/Resources/include -DNDEBUG - I/usr/local/include -I"/Library/Frameworks/R.framework/Versions/3.0/Resources/library/Matrix/include" -I"/Library/Frameworks/R.framework/Versions/3.0/Resources/library/stats/include" -fPIC -mtune=core2 -g -O2 -c init.c -o init.o
/bin/sh: llvm-gcc-4.2: command not found
make: *** [init.o] Error 127
ERROR: compilation failed for package ‘lme4’
removing ‘/Library/Frameworks/R.framework/Versions/3.0/Resources/library/lme4’
restoring previous ‘/Library/Frameworks/R.framework/Versions/3.0/Resources/library/lme4’
Warning in install.packages :
installation of package ‘/Users/nanli/Downloads/lme4_0.999999-2.tar.gz’ had non-zero exit status
任何人都有想法如何解决这个问题？