In a gcc invocation, cc1 fails with a "Not a directory" error when compiling a trivial file if there is a file (not a directory) named "lib" in the parent to the working directory.
To recreate it: bash-3.2# mkdir temp bash-3.2# cd temp bash-3.2# mkdir temp1 bash-3.2# touch lib bash-3.2# cd temp1 bash-3.2# cat>utl1.c<<EOF > void fun1(){} > EOF bash-3.2# gcc -c utl1.c cc1: error: ../lib/gcc/i686-pc-linux-gnu/4.2.1/include: Not a directory cc1: error: ../lib/gcc/i686-pc-linux-gnu/4.2.1/../../../../i686-pc-linux-gnu/include: Not a directory gcc was built as follows: ../gcc-4.2.1/configure --prefix=/usr\ --libexecdir=/usr/lib --enable-shared --enable-threads=posix\ --enable-__cxa_atexit --enable-languages=c,c++\ --disable-bootstrap make make install when run verbosely, gcc produces the following output: bash-3.2# gcc -c -v utl1.c Using built-in specs. Target: i686-pc-linux-gnu Configured with: ../gcc-4.2.1/configure --prefix=/usr --libexecdir=/usr/lib --enable-shared --enable-threads=posix --enable-__cxa_atexit --enable-languages=c,c++ --disable-bootstrap Thread model: posix gcc version 4.2.1 /usr/lib/gcc/i686-pc-linux-gnu/4.2.1/cc1 -quiet -v -iprefix ../lib/gcc/i686-pc-linux-gnu/4.2.1/ utl1.c -quiet -dumpbase utl1.c -mtune=generic -auxbase utl1 -version -o /tmp/ccsAiCrL.s cc1: error: ../lib/gcc/i686-pc-linux-gnu/4.2.1/include: Not a directory cc1: error: ../lib/gcc/i686-pc-linux-gnu/4.2.1/../../../../i686-pc-linux-gnu/include: Not a directory ignoring nonexistent directory "/usr/local/include" ignoring nonexistent directory "/usr/lib/gcc/i686-pc-linux-gnu/4.2.1/../../../../i686-pc-linux-gnu/include" #include "..." search starts here: #include <...> search starts here: /usr/lib/gcc/i686-pc-linux-gnu/4.2.1/include /usr/include End of search list. GNU C version 4.2.1 (i686-pc-linux-gnu) compiled by GNU C version 4.2.1. GGC heuristics: --param ggc-min-expand=81 --param ggc-min-heapsize=97102 -- Summary: cc1 fails with "Not a directory" on trivial file Product: gcc Version: 4.2.1 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: af804 at bfn dot org GCC build triplet: i686-pc-linux-gnu GCC host triplet: i686-pc-linux-gnu GCC target triplet: i686-pc-linux-gnu http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34748