svn build error

/bin/sh "/usr/ports/opt/subversion/work/src/subversion-1.9.0/libtool" --tag=CC --silent --mode=compile gcc -std=c90  -DLINUX -D_REENTRANT -D_GNU_SOURCE   -O2 -march=x86-64 -pipe   -pthread -O2 -march=x86-64 -pipe  -I./subversion/include -I./subversion -I/usr/include/apr-1   -I/usr/include/apr-1 -I/usr/include -I/usr/include/serf-1   -o subversion/libsvn_fs_x/dag.lo -c subversion/libsvn_fs_x/dag.c
gcc: error: subversion/libsvn_fs_x/dag.c: No such file or directory
gcc: fatal error: no input files
compilation terminated.
Makefile:762: recipe for target 'subversion/libsvn_fs_x/dag.lo' failed
make: *** [subversion/libsvn_fs_x/dag.lo] Error 1