title: Installing R packages
body: <p>When I have tried to install some R packages such as Rgraphviz, I get the following error:</p>
  
  <pre><code>install.packages("Rgraphviz_2.12.0.tar.gz",repos=NULL,type="source")
  * installing *source* package 'Rgraphviz' ...
  
  **********************************************
  WARNING: this package has a configure script
       It probably needs manual configuration
  **********************************************
  
  
  ** libs
  gcc -m32 -I"C:/PROGRA~1/R/R-31~1.2/include" -DNDEBUG     -        
  I"d:/RCompile/CRANpkg/extralibs64/local/include"  -                                
  Ilibwin/i386/include/graphviz -DHAVE_STDBOOL_H=1 -DHAVE_BOOL=1 - 
  DGRAPHVIZ_MAJOR=2 -DGRAPHVIZ_MINOR=28 -DGRAPHVIZ_STATIC   -O3 -Wall  -
  std=gnu99 -mtune=core2 -c LL_funcs.c -o LL_funcs.o
  gcc: unrecognized option `-std=gnu99'
  d:\RCompile\CRANpkg\extralibs64\local\include\.: Permission denied
  make.exe: *** [LL_funcs.o] Error 1
  Warning: running command 'make -f "Makevars.win" -f "C:/PROGRA~1/R/R-    
  31~1.2/etc/i386/Makeconf" -f "C:/PROGRA~1/R/R-31~1.2/share/make/winshlib.mk"  
  SHLIB="Rgraphviz.dll" OBJECTS="LL_funcs.o Rgraphviz.o RgraphvizInit.o   
  agopen.o agread.o agwrite.o bezier.o buildEdgeList.o buildNodeList.o    
  doLayout.o graphvizVersion.o init.o"' had status 2
  ERROR: compilation failed for package 'Rgraphviz'
  * removing 'C:/Program Files/R/R-3.1.2/library/Rgraphviz'
  Warning messages:
  1: running command '"C:/PROGRA~1/R/R-31~1.2/bin/i386/R" CMD INSTALL -l     
  "C:\Program Files\R\R-3.1.2\library" "Rgraphviz_2.12.0.tar.gz"' had status 1 
   2: In install.packages("Rgraphviz_2.12.0.tar.gz", repos = NULL, type =    
   "source") :
   installation of package ‘Rgraphviz_2.12.0.tar.gz’ had non-zero exit status
  </code></pre>
  
  <p>I am mostly appreciate any comment.</p>