chore(php-shim): drop the HHVM_VERSION constant

The constant was None and defined("HHVM_VERSION") reports it undefined, so
every branch guarded by it was dead: shirabe is a Rust binary and never runs
on HHVM. HhvmDetector keeps probing for an `hhvm` binary in PATH, which is
what actually produces the hhvm platform package.

Two of the dropped branches ask about the PHP runtime that consumes the
result rather than about shirabe itself -- the class loader's Hack file
lookup and the class map parser's enum scanning -- so both get a
TODO(php-runtime) marker.

1 files changed, 1 insertions, 3 deletions

diff --git a/crates/shirabe-php-shim/src/runtime.rs b/crates/shirabe-php-shim/src/runtime.rs
index 74ea8350..254a2fe9 100644
--- a/crates/shirabe-php-shim/src/runtime.rs
+++ b/crates/shirabe-php-shim/src/runtime.rs
@@ -13,8 +13,6 @@ pub const PHP_WINDOWS_VERSION_MAJOR: i64 = 0;
 pub const PHP_WINDOWS_VERSION_MINOR: i64 = 0;
 pub const PHP_WINDOWS_VERSION_BUILD: i64 = 0;
 
-pub const HHVM_VERSION: Option<&str> = None;
-
 pub const E_ALL: i64 = 32767;
 pub const E_WARNING: i64 = 2;
 pub const E_NOTICE: i64 = 8;
@@ -40,7 +38,7 @@ pub const PHP_OS: &str = match std::env::consts::OS.as_bytes() {
 
 // Models the constants defined in a standard modern PHP CLI environment on a
 // non-Windows platform with the common extensions loaded (curl, openssl, json).
-// Windows-only, HHVM and Composer-bootstrap constants are reported undefined.
+// Windows-only and Composer-bootstrap constants are reported undefined.
 pub fn defined(name: &str) -> bool {
     matches!(
         name,