The declaration of main in gdb.base/label.c is incorrect & fails to
compile under Clang:

../../../src/gdb/7.5/gdb/testsuite/gdb.base/label.c:4:1: error: second
parameter of 'main' (argument array) must be of type 'char **'
main (int argc, char *argv)
^

The attached patch fixes this by adding the missing '*' to the second parameter.