Support missing pcre2_set_depth_limit() function

Code taken from varnish-cache

configure.ac

@@ -69,6 +69,44 @@ AC_PATH_PROG([VARNISHTEST], [varnishtest], [],
 AC_PATH_PROG([VARNISHD], [varnishd], [],
     [$LIBVARNISHAPI_SBINDIR:$LIBVARNISHAPI_BINDIR:$PATH])
 
+m4_ifndef([PKG_PROG_PKG_CONFIG], [m4_fatal([pkg.m4 missing, please install pkg-config])])
+PKG_PROG_PKG_CONFIG
+if test -n $PKG_CONFIG; then
+   PKG_CHECK_MODULES([PCRE2], [libpcre2-8])
+else
+   AC_CHECK_PROG(PCRE2_CONFIG, pcre2-config, pcre2-config)
+   AC_ARG_WITH(pcre2-config,
+	       AS_HELP_STRING([--with-pcre2-config=PATH],
+			      [Location of PCRE2 pcre2-config (auto)]),
+	       [pcre2_config="$withval"],
+	       [pcre2_config=""])
+
+  if test "x$pcre2_config" != "x" ; then
+    AC_MSG_CHECKING(for $pcre2_config)
+
+    if test -f $pcre2_config ; then
+      PCRE2_CONFIG=$pcre2_config
+      AC_MSG_RESULT(yes)
+    else
+      AC_MSG_RESULT(no - searching PATH)
+    fi
+  fi
+  if test "x$PCRE2_CONFIG" = "x"; then
+    AC_CHECK_PROGS(PCRE2_CONFIG, pcre2-config)
+  fi
+  PCRE2_CFLAGS=`$PCRE2_CONFIG --cflags`
+  PCRE2_LIBS=`$PCRE2_CONFIG --libs8`
+fi
+AC_SUBST(PCRE2_CFLAGS)
+AC_SUBST(PCRE2_LIBS)
+
+save_LIBS="${LIBS}"
+LIBS="${LIBS} ${PCRE2_LIBS}"
+AC_CHECK_FUNCS([pcre2_set_depth_limit_8], [
+  AC_DEFINE([HAVE_PCRE2_SET_DEPTH_LIMIT], [1], [Use pcre2_set_depth_limit()])
+])
+LIBS="${save_LIBS}"
+
 # This corresponds to FreeBSD's WARNS level 6
 DEVELOPER_CFLAGS="-Wall -Wstrict-prototypes -Wmissing-prototypes -Wpointer-arith -Wreturn-type -Wcast-qual -Wwrite-strings -Wswitch -Wshadow -Wcast-align -Wchar-subscripts -Winline -Wnested-externs -Wredundant-decls -Wformat"
 

src/vmod_re.c

@@ -42,6 +42,10 @@
 
 #include "vcc_if.h"
 
+#if !HAVE_PCRE2_SET_DEPTH_LIMIT
+#  define pcre2_set_depth_limit(r, d) pcre2_set_recursion_limit(r, d)
+#endif
+
 #define MAX_MATCHES	11
 #define MAX_OV		((MAX_MATCHES) * 2)