sys: disable jit on apple >~= aarch64

This disables the JIT on a few targets because it doesn't appear to
build. For example, Clang fails with:

    Undefined symbols for architecture arm64:
      "___clear_cache", referenced from:
          _sljit_generate_code in libforeign.a(pcre2_jit_compile.o)
    ld: symbol(s) not found for architecture arm64

PR #16

Author: b8591340

pcre2-sys/build.rs

@@ -93,13 +93,14 @@ fn main() {
         .define("PARENS_NEST_LIMIT", "250")
         .define("PCRE2_STATIC", "1")
         .define("STDC_HEADERS", "1")
-        .define("SUPPORT_JIT", "1")
         .define("SUPPORT_PCRE2_8", "1")
         .define("SUPPORT_UNICODE", "1");
     if target.contains("windows") {
         builder.define("HAVE_WINDOWS_H", "1");
     }
 
+    enable_jit(&target, &mut builder);
+
     // Copy PCRE2 headers. Typically, `./configure` would do this for us
     // automatically, but since we're compiling by hand, we do it ourselves.
     let include = out.join("include");
@@ -151,3 +152,29 @@ fn pcre2_sys_static() -> Option<bool> {
         }
     }
 }
+
+// On `aarch64-apple-ios` clang fails with the following error.
+//
+//     Undefined symbols for architecture arm64:
+//       "___clear_cache", referenced from:
+//           _sljit_generate_code in libforeign.a(pcre2_jit_compile.o)
+//     ld: symbol(s) not found for architecture arm64
+//
+// aarch64-apple-tvos         https://bugreports.qt.io/browse/QTBUG-62993?gerritReviewStatus=All
+// aarch64-apple-darwin       https://github.com/Homebrew/homebrew-core/pull/57419
+// x86_64-apple-ios           disabled for device–simulator consistency (not tested)
+// x86_64-apple-tvos          disabled for device–simulator consistency (not tested)
+// armv7-apple-ios            assumed equivalent to aarch64-apple-ios (not tested)
+// armv7s-apple-ios           assumed equivalent to aarch64-apple-ios (not tested)
+// i386-apple-ios             assumed equivalent to aarch64-apple-ios (not tested)
+// x86_64-apple-ios-macabi    disabled out of caution (not tested) (needs attention)
+//
+// We may want to monitor developments on the `aarch64-apple-darwin` front as they may end up
+// propagating to all `aarch64`-based targets and the `x86_64` equivalents.
+fn enable_jit(target: &str, builder: &mut cc::Build) {
+    if !target.starts_with("aarch64-apple") &&
+        !target.contains("apple-ios") &&
+        !target.contains("apple-tvos") {
+        builder.define("SUPPORT_JIT", "1");
+    }
+}