From 9fa53f1a1bde42381c10d14b5b246420683733b1 Mon Sep 17 00:00:00 2001
From: Jim Meyering <meyering@redhat.com>
Date: Wed, 24 Mar 2010 08:40:05 +0100
Subject: build: do not use pkg-config to test for PCRE support

* configure.ac: Do not use PKG_PROG_PKG_CONFIG or PKG_CHECK_MODULES.
Do not modify CPPFLAGS; that belongs to those who invoke make.
Instead, use autoconf's AC_CHECK_HEADERS and AC_SEARCH_LIBS via the
new macro, gl_FUNC_PCRE, defined in...
* m4/pcre.m4 (gl_FUNC_PCRE): New macro, to handle pcre-related
configure-time tests.
* src/Makefile.am (grep_LDADD): Use LIB_PCRE, not PCRE_LIBS.
* src/pcresearch.c: Test HAVE_LIBPCRE via "#if", not "#ifdef".
All other cpp tests of this symbol used "#if".
Prompted by a suggestion from Bruno Haible.
* NEWS (Build-related): Mention this.
---
 NEWS             |  4 ++++
 configure.ac     | 19 +------------------
 m4/pcre.m4       | 45 +++++++++++++++++++++++++++++++++++++++++++++
 src/Makefile.am  |  2 +-
 src/pcresearch.c |  2 +-
 5 files changed, 52 insertions(+), 20 deletions(-)
 create mode 100644 m4/pcre.m4

diff --git a/NEWS b/NEWS
index 2e0414e8..115fe762 100644
--- a/NEWS
+++ b/NEWS
@@ -2,6 +2,10 @@ GNU grep NEWS                                    -*- outline -*-
 
 * Noteworthy changes in release ?.? (????-??-??) [?]
 
+** Build-related
+
+  configure no longer relies on pkg-config to detect PCRE support.
+
 
 * Noteworthy changes in release 2.6.1 (2010-03-25) [stable]
 
diff --git a/configure.ac b/configure.ac
index 474a9ae4..f43c92fc 100644
--- a/configure.ac
+++ b/configure.ac
@@ -33,15 +33,6 @@ AM_SILENT_RULES([yes]) # make --enable-silent-rules the default.
 
 AC_CONFIG_HEADERS([config.h:config.hin])
 
-dnl Check for arguments
-AC_ARG_ENABLE(perl-regexp,
- [  --disable-perl-regexp           disable perl-regexp],
- [case "${enableval}" in
-  yes) testpcre=yes ;;
-  no)  testpcre=no ;;
-  *)   AC_MSG_ERROR(bad value ${enableval} for --disable-perl-regexp) ;;
- esac],[testpcre=yes])
-
 dnl Checks for programs.
 AC_CANONICAL_HOST
 AC_PROG_AWK
@@ -158,15 +149,7 @@ if test "$ac_use_included_regex" = no; then
   AC_MSG_WARN([Included lib/regex.c not used])
 fi
 
-# support for pcre
-PKG_PROG_PKG_CONFIG
-if test x"$testpcre" = x"yes"; then
-  PKG_CHECK_MODULES(PCRE, [libpcre],
-	  [AC_DEFINE([HAVE_LIBPCRE], 1,
-	    [Define to 1 if you have the `pcre' library (-lpcre).])
-	   CPPFLAGS="$CPPFLAGS $PCRE_CFLAGS"],
-	  [:])
-fi
+gl_FUNC_PCRE
 
 AC_CONFIG_FILES([
   Makefile
diff --git a/m4/pcre.m4 b/m4/pcre.m4
new file mode 100644
index 00000000..001806e0
--- /dev/null
+++ b/m4/pcre.m4
@@ -0,0 +1,45 @@
+# pcre.m4 - check for libpcre support
+# serial 1
+
+# Copyright (C) 2010 Free Software Foundation, Inc.
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_PCRE],
+[
+  AC_ARG_ENABLE([perl-regexp],
+    AC_HELP_STRING([--disable-perl-regexp],
+                   [disable perl-regexp (pcre) support]),
+    [case $enableval in
+       yes|no) test_pcre=$enableval;;
+       *) AC_MSG_ERROR([invalid value $enableval for --disable-perl-regexp]);;
+     esac],
+    [test_pcre=yes])
+
+  LIB_PCRE=
+  AC_SUBST([LIB_PCRE])
+  use_pcre=no
+
+  if test x"$test_pcre" = x"yes"; then
+    AC_CHECK_HEADERS([pcre.h])
+    if test $ac_cv_header_pcre_h = yes; then
+      pcre_saved_LIBS=$LIBS
+      AC_SEARCH_LIBS([pcre_compile], [pcre],
+	[test "$ac_cv_search_pcre_compile" = "none required" ||
+	 LIB_PCRE=$ac_cv_search_pcre_compile])
+      AC_CHECK_FUNCS([pcre_compile])
+      LIBS=$pcre_saved_LIBS
+      if test $ac_cv_func_pcre_compile = yes; then
+	use_pcre=yes
+      fi
+    fi
+    if test $use_pcre = no; then
+      AC_MSG_WARN([libpcre development library was not found or not usable.])
+      AC_MSG_WARN([AC_PACKAGE_NAME will be built without pcre support.])
+    fi
+  fi
+
+  AC_DEFINE_UNQUOTED([HAVE_LIBPCRE], [`test $use_pcre != yes; echo $?`],
+    [Define to 1 if you have the `pcre' library (-lpcre).])
+])
diff --git a/src/Makefile.am b/src/Makefile.am
index 08f7aacf..a5d8ecaa 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -35,7 +35,7 @@ libgrep_a_SOURCES = kwset.c dfa.c searchutils.c dfasearch.c kwsearch.c \
 # replacement functions defined in libgreputils.a.
 LDADD = libgrep.a ../lib/libgreputils.a $(LIBINTL) ../lib/libgreputils.a
 
-grep_LDADD = $(LDADD) $(PCRE_LIBS)
+grep_LDADD = $(LDADD) $(LIB_PCRE)
 localedir = $(datadir)/locale
 INCLUDES = -I$(top_srcdir)/lib -DLOCALEDIR=\"$(localedir)\"
 
diff --git a/src/pcresearch.c b/src/pcresearch.c
index 4dedf245..6a82be28 100644
--- a/src/pcresearch.c
+++ b/src/pcresearch.c
@@ -20,7 +20,7 @@
 
 #include <config.h>
 #include "search.h"
-#ifdef HAVE_LIBPCRE
+#if HAVE_LIBPCRE
 # include <pcre.h>
 #endif
 
-- 
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