Use /usr/bin/env to make ex1.c and ex4.c on any systems, wherever is installed tcc.
This reverts commit cb2138f8b0.
cb2138f8b0
Use @BINDIR@ in shebang of examples to put the right path on the target system. That is, use #!/usr/local/bin/tcc if tcc is installed in /usr/local/bin and #!/usr/bin/tcc if tcc is installed in /usr/bin/tcc.