getCExpr() emitted int class constants, property defaults and parameter
defaults with strval(), so `const M = PHP_INT_MIN;` produced
`ZVAL_LONG(&const_M_value, -9223372036854775808)`. C parses that as
unary minus applied to the literal 9223372036854775808, which exceeds
long long and is ill-formed, so the generated extension source does not
compile. The expression path already handles this via genIntegerLiteral
(ZEND_LONG_MIN); give the stub metadata path the same spelling.
The float paths (17-digit round-trip, -0.0 sign, INF/NAN) were already
fixed upstream in 2d81626a; the new test pins those literals down
together with the int boundary values.
Alessio Giacobbe