zsh: use libpcre2 instead of libpcre

Changes:
 - use libpcre2 instead of libpcre
 - patch Src/Modules/pcre.c: source from mainstream's git (23.9.2023)
 - patch configure.ac and config.h.in: replace libpcre with libpcre2 and remove missing AC_PROG_LN
 - patch Src/Makefile.in: use LN_S instead of LN
 - patch Test/V07pcre.ztst: add some libpcre2 specific tests
 - use configure.ac instead of traditional configure: git version no longer supports traditional configure script, so it was easier to backport configure.ac for libpcre2

Auto-tools was missing AC_PROG_LN, configure.ac and Makefile.in patched to use AC_PROG_LN_S instead.

PKG_FIXUP:=autoreconf sets configure.ac used over traditional configure script.

Patches are split to 2.
010-use-libpcre2.patch replaces libpcre with libpcre2.
020-replace-missing-autotools-ln-with-ln_s.patch fixes autotools configure and install scripts so they are compatible with openwrt build system.

changes to replace libpcre with libpcre2 are based on
backporting of zsh-users/zsh@b4d1c756 pcre2 code.

Remarks:
Patch replacing libpcre with libpcre2 becomes obsolete when zsh is released next time.
It should then be removed.

Signed-off-by: Oskari Rauta <[email protected]>

utils/zsh/Makefile

@@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=zsh
 PKG_VERSION:=5.9
-PKG_RELEASE:=1
+PKG_RELEASE:=2
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.xz
 PKG_SOURCE_URL:=@SF/zsh
@@ -20,6 +20,7 @@ PKG_LICENSE:=ZSH
 PKG_LICENSE_FILES:=LICENCE
 PKG_CPE_ID:=cpe:/a:zsh_project:zsh
 
+PKG_FIXUP:=autoreconf
 PKG_BUILD_PARALLEL:=1
 PKG_INSTALL:=1
 PKG_BUILD_FLAGS:=gc-sections lto
@@ -31,7 +32,7 @@ define Package/zsh
   CATEGORY:=Utilities
   SUBMENU:=Shells
   TITLE:=The Z shell
-  DEPENDS:=+libcap +libncurses +libncursesw +libpcre +librt
+  DEPENDS:=+libcap +libncurses +libncursesw +libpcre2 +librt
   URL:=https://www.zsh.org/
 endef