Tweak inline-heuristic and use current-stack size
try_mem_offset() step calculation is part of the main-if
Prevent inlining of functions with VM-arguments

This simplifies the code handling remapping of VM-argument symbols
to their stack-spilt equivalent.
Warn about inlining __builtin_frame_address() (and fix test)
Factor out v_new_reg() in x86_fp_conv()
Ensure V_CONST_F out_vals are loaded in x86_fp_conv()

Inline functions may inline functions that do constant operations
on floats, e.g.

float add(float a){ return a + 1; }

so we want inline-float-calls to maintain the rvalueness of the float
argument when possible. But we also want the rvalue-float to convert
to a label + load (x86) in other cases, e.g.

void va_func(char *, ...);
float print(float f){ va_func("", f); }

Here we need to promote 'f' to double and this requires V_REG, not
V_CONST_F, so x86_fp_conv() now additionally tests for this.
Fix ({ ... }) outside of functions
Update certain tests with -fno-inline-functions