fix(pcre2): only change m4 script and rename ac vars

Signed-off-by: Felipe Zipitria <felipe.zipitria@owasp.org>

Author: fzipi

build/ax_check_pcre2.m4

@@ -0,0 +1,172 @@
+# ===========================================================================
+#      https://www.gnu.org/software/autoconf-archive/ax_check_pcre2.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_CHECK_PCRE2([bits], [action-if-found], [action-if-not-found])
+#
+# DESCRIPTION
+#
+#   Search for an installed libpcre2-8 library. If nothing was specified
+#   when calling configure, it searches first in /usr/local and then in
+#   /usr, /opt/local and /sw. If the --with-pcre2=DIR is specified, it will
+#   try to find it in DIR/include/pcre2.h and DIR/lib/libpcre2-8. If
+#   --without-pcre2 is specified, the library is not searched at all.
+#
+#   If 'bits' is empty or '8', PCRE2 8-bit character support is checked
+#   only. If 'bits' contains '16', PCRE2 8-bit and 16-bit character support
+#   are checked. If 'bits' contains '32', PCRE2 8-bit and 32-bit character
+#   support are checked. When 'bits' contains both '16' and '32', PCRE2
+#   8-bit, 16-bit, and 32-bit character support is checked.
+#
+#   If either the header file (pcre2.h), or the library (libpcre2-8) is not
+#   found, or the specified PCRE2 character bit width is not supported,
+#   shell commands 'action-if-not-found' is run. If 'action-if-not-found' is
+#   not specified, the configuration exits on error, asking for a valid
+#   PCRE2 installation directory or --without-pcre2.
+#
+#   If both header file and library are found, and the specified PCRE2 bit
+#   widths are supported, shell commands 'action-if-found' is run. If
+#   'action-if-found' is not specified, the default action appends
+#   '-I${PCRE2_HOME}/include' to CPFLAGS, appends '-L$PCRE2_HOME}/lib' to
+#   LDFLAGS, prepends '-lpcre2-8' to LIBS, and calls AC_DEFINE(HAVE_PCRE2).
+#   You should use autoheader to include a definition for this symbol in a
+#   config.h file. Sample usage in a C/C++ source is as follows:
+#
+#     #ifdef HAVE_PCRE2
+#     #define PCRE2_CODE_UNIT_WIDTH 8
+#     #include <pcre2.h>
+#     #endif /* HAVE_PCRE2 */
+#
+# LICENSE
+#
+#   Copyright (c) 2020 Robert van Engelen <engelen@acm.org>
+#
+#   This program is free software; you can redistribute it and/or modify it
+#   under the terms of the GNU General Public License as published by the
+#   Free Software Foundation; either version 2 of the License, or (at your
+#   option) any later version.
+#
+#   This program is distributed in the hope that it will be useful, but
+#   WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+#   Public License for more details.
+#
+#   You should have received a copy of the GNU General Public License along
+#   with this program. If not, see <https://www.gnu.org/licenses/>.
+#
+#   As a special exception, the respective Autoconf Macro's copyright owner
+#   gives unlimited permission to copy, distribute and modify the configure
+#   scripts that are the output of Autoconf when processing the Macro. You
+#   need not follow the terms of the GNU General Public License when using
+#   or distributing such scripts, even though portions of the text of the
+#   Macro appear in them. The GNU General Public License (GPL) does govern
+#   all other use of the material that constitutes the Autoconf Macro.
+#
+#   This special exception to the GPL applies to versions of the Autoconf
+#   Macro released by the Autoconf Archive. When you make and distribute a
+#   modified version of the Autoconf Macro, you may extend this special
+#   exception to the GPL to apply to your modified version as well.
+
+# This is the original upstream check for pcre2 from autoconf-archive website,
+# with these changes:
+# - instead of HAVE_PCRE2 -> WITH_PCRE2 to maintain compatibility
+# - changed CPPFLAGS, LDFLAGS and LIBS to be prefixed with PCRE2_, and do not
+#   concat with previous definitions
+
+#serial 2
+
+AC_DEFUN([AX_CHECK_PCRE2],
+#
+# Handle user hints
+#
+[AC_MSG_CHECKING(if PCRE2 is wanted)
+pcre2_places="/usr/local /usr /opt/local /sw"
+AC_ARG_WITH([pcre2],
+[  --with-pcre2=DIR        root directory path of PCRE2 installation @<:@defaults to
+                          /usr/local or /usr if not found in /usr/local@:>@
+  --without-pcre2         to disable PCRE2 usage completely],
+[if test "$withval" != "no" ; then
+  AC_MSG_RESULT(yes)
+  if test -d "$withval"
+  then
+    pcre2_places="$withval $pcre2_places"
+  else
+    AC_MSG_WARN([Sorry, $withval does not exist, checking usual places])
+  fi
+else
+  pcre2_places=""
+  AC_MSG_RESULT(no)
+fi],
+[AC_MSG_RESULT(yes)])
+#
+# Locate PCRE2, if wanted
+#
+if test -n "${pcre2_places}"
+then
+  # check the user supplied or any other more or less 'standard' place:
+  #   Most UNIX systems      : /usr/local and /usr
+  #   MacPorts / Fink on OSX : /opt/local respectively /sw
+  for PCRE2_HOME in ${pcre2_places} ; do
+    if test -f "${PCRE2_HOME}/include/pcre2.h"; then break; fi
+    PCRE2_HOME=""
+  done
+
+  PCRE2_OLD_LDFLAGS=$LDFLAGS
+  PCRE2_OLD_CPPFLAGS=$CPPFLAGS
+  if test -n "${PCRE2_HOME}"; then
+    PCRE2_LDFLAGS="-L${PCRE2_HOME}/lib"
+    PCRE2_CFLAGS="-I${PCRE2_HOME}/include"
+  fi
+  AC_LANG_PUSH([C])
+  AC_CHECK_LIB([pcre2-8], [pcre2_compile_8], [pcre2_cv_libpcre2=yes], [pcre2_cv_libpcre2=no])
+  AC_CHECK_HEADER([pcre2.h], [pcre2_cv_pcre2_h=yes], [pcre2_cv_pcre2_h=no], [#define PCRE2_CODE_UNIT_WIDTH 8])
+  case "$1" in
+  *16*)
+    AC_CHECK_LIB([pcre2-16], [pcre2_compile_16], [pcre2_cv_libpcre2_16=yes], [pcre2_cv_libpcre2_16=no])
+    AC_CHECK_HEADER([pcre2.h], [pcre2_cv_pcre2_16_h=yes], [pcre2_cv_pcre2_16_h=no], [#define PCRE2_CODE_UNIT_WIDTH 16])
+    if test "$pcre2_cv_libpcre2_16" = "no" || test "$pcre2_cv_pcre2_16_h" = "no"; then
+      pcre2_cv_libpcre2=no
+    fi
+    ;;
+  esac
+  case "$1" in
+  *32*)
+    AC_CHECK_LIB([pcre2-32], [pcre2_compile_32], [pcre2_cv_libpcre2_32=yes], [pcre2_cv_libpcre2_32=no])
+    AC_CHECK_HEADER([pcre2.h], [pcre2_cv_pcre2_32_h=yes], [pcre2_cv_pcre2_32_h=no], [#define PCRE2_CODE_UNIT_WIDTH 32])
+    if test "$pcre2_cv_libpcre2_32" = "no" || test "$pcre2_cv_pcre2_32_h" = "no"; then
+      pcre2_cv_libpcre2=no
+    fi
+  esac
+  AC_LANG_POP([C])
+  if test "$pcre2_cv_libpcre2" = "yes" && test "$pcre2_cv_pcre2_h" = "yes"
+  then
+    #
+    # If both library and header were found, action-if-found
+    #
+    m4_ifblank([$2],[
+                PCRE2_CFLAGS="-I${PCRE2_HOME}/include"
+                PCRE2_LDFLAGS="-L${PCRE2_HOME}/lib"
+                PCRE2_LDADD="-lpcre2-8"
+		AC_SUBST(PCRE2_CFLAGS)
+		AC_SUBST(PCRE2_LDFLAGS)
+		AC_SUBST(PCRE2_LDADD)
+                AC_DEFINE([WITH_PCRE2], [1],
+                          [Define to 1 if you have `PCRE2' library (-lpcre2-$1)])
+               ],[
+                # Restore variables
+                LDFLAGS="$PCRE2_OLD_LDFLAGS"
+                CPPFLAGS="$PCRE2_OLD_CPPFLAGS"
+                $2
+               ])
+  else
+    #
+    # If either header or library was not found, action-if-not-found
+    #
+    m4_default([$3],[
+                AC_MSG_ERROR([either specify a valid PCRE2 installation with --with-pcre2=DIR or disable PCRE2 usage with --without-pcre2])
+                ])
+  fi
+fi
+])