[grandixximo]

While a sub is being defined, read_named_parameter() skips the "Named parameter not defined" error for an undefined named parameter, but it returned INTERP_OK without writing *double_ptr. The caller's local double stayed uninitialized, and read_real_value() then checked it with isnan()/isinf().

On i386 the leftover stack value is sometimes NaN, so a line like o#<sub> call inside a sub definition fails with Calculation resulted in 'not a number'. This is the intermittent tests/interp/oword-bug315-p2 failure on the i386 package job, for example on the Weblate PR #4723, which only touches .po files.

Valgrind shows the read on x86-64 as well:

Conditional jump or move depends on uninitialised value(s)
   at Interp::read_real_value (interp_read.cc:2860)
   by Interp::read_integer_value (interp_read.cc:791)
   by Interp::read_o (interp_read.cc:1620)
 Uninitialised value was created by a stack allocation
   at Interp::read_integer_value (interp_read.cc:788)

The fix sets the value to 0.0 in that branch. With it, valgrind is clean on oword-bug315-p2 and tests/interp passes (98/98).