Unused $CPP is shown as a configure option
In configure, we were calling AC_PROG_CPP
but never making use of the
$CPP variable it sets or reads.
The issue is $CPP will show up in the --help output of configure, falsely advertising a configuration option that does nothing.
The reason we don't use the $CPP variable is because HS_CPP_CMD is
expected to be a single command (without flags), but AC_PROG_CPP, when
CPP is unset, will set said variable to something like /usr/bin/gcc -E
.
Instead, we configure HS_CPP_CMD through $CC.
Fixed in !10431 (closed)