+.It Fl f Ns Cm bail-on-werror
+When a warning is treated as an error, and this option is set (which
+it is by default), it is like any other error and will cause
+compilation to stop. When disabling this flag by using
+\-fno-bail-on-werror, compilation will continue until the end, but no
+output is generated. Instead the first such error message's context is
+shown.
+.It Fl f Ns Cm loop-labels
+Allow loops to be labeled, and allow 'break' and 'continue' to take an
+optional label to decide which loop to actually jump out of or
+continue.
+.Bd -literal -offset indent
+for :outer (i = 0; i < n; ++i) {
+ while (inner) {
+ ...;
+ if (something)
+ continue outer;
+ }
+}
+.Ed
+.It Fl f Ns Cm untyped-nil
+Adds a global named 'nil' which is of no type and can be assigned to
+anything. No typechecking will be performed on assignments. Assigning
+to it is forbidden, using it in any other kind of expression is also
+not allowed.
+.sp
+Note that this is different from fteqcc's __NULL__: In fteqcc,
+__NULL__ maps to the integer written as '0i'. It's can be assigned to
+function pointers and integers, but it'll error about invalid
+instructions when assigning it to floats without enabling the FTE
+instruction set. There's also a bug which allows it to be assigned to
+vectors, for which the source will be the global at offset 0, meaning
+the vector's y and z components will contain the OFS_RETURN x and y
+components.
+.sp
+In that gmqcc the nil global is an actual global filled with zeroes,
+and can be assigned to anything including fields, vectors or function
+pointers, and they end up becoming zeroed.
+.It Fl f Ns Cm permissive
+Various effects, usually to weaken some conditions.
+.Bl -tag -width indent -offset indent
+.It with Fl f Ns Cm untyped-nil
+Allow local variables named
+.Ql nil Ns .
+(This will not allow declaring a global of that name.)
+.El
+.It Fl f Ns Cm variadic-args
+Allow variadic parameters to be accessed by QC code. This can be
+achieved via the '...' function, which takes a parameter index and a
+typename.
+.Pp
+Example:
+.Bd -literal -offset indent
+void vafunc(string...count) {
+ float i;
+ for (i = 0; i < count; ++i)
+ print(...(i, string), "\\n");
+}
+.Ed
+.It Fl f Ns Cm legacy-vector-maths
+Most Quake VMs, including the one from FTEQW or up till recently
+Darkplaces, do not cope well with vector instructions with overlapping
+input and output. This option will avoid producing such code.
+.It Fl f Ns Cm expressions-for-builtins
+Usually builtin-numbers are just immediate constants. With this flag
+expressions can be used, as long as they are compile-time constant.
+.Pp
+Example:
+.Bd -literal -offset indent
+void printA() = #1; // the usual way
+void printB() = #2-1; // with a constant expression
+.Ed
+.It Fl f Ns Cm return-assignments
+Enabiling this option will allow assigning values or expressions to the
+return keyword as if it were a local variable of the same type as the
+function's signature's return type.
+.Pp
+Example:
+.Bd -literal -offset indent
+float bar() { return 1024; }
+float fun() {
+ return = bar();
+ return; // returns value of bar
+}
+.Ed
+.It Fl f Ns Cm unsafe-varargs
+When passing on varargs to a different functions, this turns some
+static error cases into warnings. Like when the caller's varargs are
+restricted to a different type than the callee's parameter. Or a list
+of unrestricted varargs is passed into restricted varargs.
+.El
+.Sh OPTIMIZATIONS
+.Bl -tag -width Ds
+.It Fl O Ns Cm peephole