pcre2: Add JIT-support for select architectures in PCRE2

- This commit adds a config-option for JIT in libpcre2.

  According to research published on
  https://rust-leipzig.github.io/regex/2017/03/28/comparison-of-regex-engines/
  this should give a 10x performance increase on JIT operations
  which can be desireable for high performance Apache mod_rewrite
  or haproxy reqrep operations.

  This option is available on all officially supported architecutres
  which are listed on https://pcre.org/current/doc/html/pcre2jit.html#SEC2.
  Furthermore, it is enabled by default on the following
  architectures: arm, i686, x86_64.

Signed-off-by: Christian Lachner <gladiac@gmail.com>

libs/pcre2/Makefile

@@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=pcre2
 PKG_VERSION:=10.32
-PKG_RELEASE:=1
+PKG_RELEASE:=2
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.bz2
 PKG_SOURCE_URL:=@SF/pcre/$(PKG_NAME)/$(PKG_VERSION)
@@ -25,6 +25,9 @@ PKG_FIXUP:=autoreconf
 PKG_BUILD_PARALLEL:=1
 PKG_INSTALL:=1
 
+PKG_CONFIG_DEPENDS:=\
+	CONFIG_PCRE2_JIT_ENABLED
+
 include $(INCLUDE_DIR)/package.mk
 
 define Package/libpcre2/default
@@ -33,6 +36,10 @@ define Package/libpcre2/default
   URL:=https://www.pcre.org/
 endef
 
+define Package/libpcre2/config
+  source "$(SOURCE)/Config.in"
+endef
+
 define Package/libpcre2
   $(call Package/libpcre2/default)
   TITLE:=A Perl Compatible Regular Expression library
@@ -53,7 +60,8 @@ TARGET_CFLAGS += $(FPIC)
 
 CONFIGURE_ARGS += \
 	--enable-pcre2-16 \
-	--enable-pcre2-32 
+	--enable-pcre2-32 \
+	$(if $(CONFIG_PCRE2_JIT_ENABLED),--enable-jit,--disable-jit)
 
 MAKE_FLAGS += \
 	CFLAGS="$(TARGET_CFLAGS)"