Forward-port macOS LuaJIT port fixes to 2026-07-20_1

Upstream's LuaJIT bump adds vcpkg-ports/ports/luajit/2026-07-20_1 and
points the filesystem-registry baseline at it. That directory is
byte-identical to 2025-07-24_1 apart from lacking the macOS fixes this
fork carries, so they would have silently stopped applying on the next
build without any textual merge conflict.

Restore all three in the new port:

- configure: pin the installed tool symlink via INSTALL_TSYMNAME so it
  doesn't collide with an existing target on the osx triplet.
- configure: restore the executable bit; portfile.cmake file(COPY)s the
  script into the source tree and the make step invokes it directly.
  Upstream's own 2025-07-24_1 shipped it 100755.
- pob-wide-crt.patch: make _lua_getenvcopy null-safe, since
  strdup(NULL) on an unset env var is UB, and cast in _lua_getenvfree
  so free() doesn't discard a const qualifier.

Both files are now byte-identical to their 2025-07-24_1 counterparts.

Not build-verified: a CMake rebuild is the real test.

Author: pathanin

vcpkg-ports/ports/luajit/2026-07-20_1/configure

@@ -77,7 +77,7 @@ all:
 	done
 
 install:
-	\$(MAKE) install \$(COMMON_OPTIONS)
+	\$(MAKE) install \$(COMMON_OPTIONS) 'INSTALL_TSYMNAME=luajit-lnk'
 	for DA in \$(DASM_ARCHS); do \\
 		mkdir -p "\$\${DESTDIR}\$(BUILDVM_PREFIX)"; \\
 		install -m 0755 "src/host/buildvm-\$\$DA\$(EXECUTABLE_SUFFIX)" "\$\${DESTDIR}\$(BUILDVM_PREFIX)/buildvm-\$\$DA\$(EXECUTABLE_SUFFIX)" || exit 1 ; \\

vcpkg-ports/ports/luajit/2026-07-20_1/pob-wide-crt.patch

@@ -393,8 +393,8 @@ index 00000000..72e9ccae
 +char* _lua_tmpnam();
 +#else
 +#define _lua_fopen(path, mode) fopen(path, mode)
-+#define _lua_getenvcopy(name) strdup(getenv(name))
-+#define _lua_getenvfree(name) free(name)
++#define _lua_getenvcopy(name) ({ char const* _lua_ev = getenv(name); _lua_ev ? strdup(_lua_ev) : (char*)0; })
++#define _lua_getenvfree(name) free((void*)(name))
 +#define _lua_remove(path) remove(path)
 +#define _lua_rename(oldpath, newpath) rename(oldpath, newpath)
 +#define _lua_system(cmd) system(cmd)