ripgrep: increase pcre2's default JIT stack size

The default stack size is 32KB, and this increases it to 10MB. 32KB is
pretty paltry in the environments in which ripgrep runs, and 10MB is
easily afforded as a maximum size. (The size limit we set for Rust's
regex engine is considerably larger.)

This was motivated due to the fack that JIT stack limits have been
observed to be hit in the wild:
https://github.com/Microsoft/vscode/issues/64606

CHANGELOG.md

@@ -91,6 +91,7 @@ Bug fixes:
   Fix bug where `-F`/`-x` weren't applied to patterns given via `-f`.
 * [BUG #1189](https://github.com/BurntSushi/ripgrep/issues/1189):
   Document cases where ripgrep may use a lot of memory.
+* BUG: Increase the default stack size for PCRE2's JIT.
 
 
 0.10.0 (2018-09-07)

src/args.rs

@@ -693,8 +693,13 @@ impl ArgMatches {
             .word(self.is_present("word-regexp"));
         // For whatever reason, the JIT craps out during regex compilation with
         // a "no more memory" error on 32 bit systems. So don't use it there.
-            builder.jit_if_available(true);
         if cfg!(target_pointer_width = "64") {
+            builder
+                .jit_if_available(true)
+                // The PCRE2 docs say that 32KB is the default, and that 1MB
+                // should be big enough for anything. But let's crank it to
+                // 10MB.
+                .max_jit_stack_size(Some(10 * (1<<20)));
         }
         if self.pcre2_unicode() {
             builder.utf(true).ucp(true);