In some Linux systems varnish will show an error after installation.
Message from C-compiler:
/bin/sh: /usr/bin/gcc: Permission denied
/bin/sh: line 0: exec: /usr/bin/gcc: cannot execute: Permission denied
Running C-compiler failed, exited with 126
VCL compilation failed
We can resolve this by correcting the permissions of gcc and ld.
#chmod 755 /usr/bin/gcc
#chmod 755 /usr/bin/ld