Ignore EINVAL errors.  This matters within user namespaces.

See:
https://github.com/NixOS/nixpkgs/issues/25901
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=802612
https://github.com/NixOS/nixpkgs/issues/10496

diff --git a/libfakeroot.c b/libfakeroot.c
index 68a95fb..70da8bc 100644
--- a/libfakeroot.c
+++ b/libfakeroot.c
@@ -792,7 +792,7 @@ int chown(const char *path, uid_t owner, gid_t group){
     r=next_lchown(path,owner,group);
   else
     r=0;
-  if(r&&(errno==EPERM))
+  if(r&&(errno==EPERM||errno==EINVAL))
     r=0;

   return r;
@@ -819,7 +819,7 @@ int lchown(const char *path, uid_t owner, gid_t group){
     r=next_lchown(path,owner,group);
   else
     r=0;
-  if(r&&(errno==EPERM))
+  if(r&&(errno==EPERM||errno==EINVAL))
     r=0;

   return r;
@@ -843,7 +843,7 @@ int fchown(int fd, uid_t owner, gid_t group){
   else
     r=0;

-  if(r&&(errno==EPERM))
+  if(r&&(errno==EPERM||errno==EINVAL))
     r=0;

   return r;
@@ -870,7 +870,7 @@ int fchownat(int dir_fd, const char *path, uid_t owner, gid_t group, int flags)
   else
     r=0;

-  if(r&&(errno==EPERM))
+  if(r&&(errno==EPERM||errno==EINVAL))
     r=0;

   return r;