pcre, pcre2: autodetect jit support, don't force-enable

PCRE JIT is not supported on most architectores: m68k, s390,
ia64 to name a few.

Example build failure is:

    $ nix build -f. pkgsCross.s390.pcre
    ...
    pcre_jit_compile.c:65:2: error: #error Unsupported architecture

The change shifts from --enable-jit[=yes] to --enable-jit=auto which
allows nixpkgs to enable jit automatically only on supported targets.

pkgs/development/libraries/pcre/default.nix

@@ -21,7 +21,7 @@ stdenv.mkDerivation rec {
   outputs = [ "bin" "dev" "out" "doc" "man" ];
 
   # Disable jit on Apple Silicon, https://github.com/zherczeg/sljit/issues/51
-  configureFlags = optional (!stdenv.hostPlatform.isRiscV && !(stdenv.hostPlatform.isDarwin && stdenv.hostPlatform.isAarch64)) "--enable-jit" ++ [
+  configureFlags = optional (!(stdenv.hostPlatform.isDarwin && stdenv.hostPlatform.isAarch64)) "--enable-jit=auto" ++ [
     "--enable-unicode-properties"
     "--disable-cpp"
   ]

pkgs/development/libraries/pcre2/default.nix

@@ -15,9 +15,7 @@ stdenv.mkDerivation rec {
   configureFlags = [
     "--enable-pcre2-16"
     "--enable-pcre2-32"
-  ] ++ lib.optional (!stdenv.hostPlatform.isRiscV &&
-                     !(stdenv.hostPlatform.isDarwin &&
-                       stdenv.hostPlatform.isAarch64)) "--enable-jit";
+  ] ++ lib.optional (!(stdenv.hostPlatform.isDarwin && stdenv.hostPlatform.isAarch64)) "--enable-jit=auto";
 
   outputs = [ "bin" "dev" "out" "doc" "man" "devdoc" ];