Updated gr-howto-write-a-block; mostly the .m4 macros and configure.ac.

Also modified pkg.m4 to restore the FOO_INCLUDEDIR functionality and
to add the FOO_CPPFLAGS variable for those times when you want only
the -I, -D and -U flags from FOO_CFLAGS.


git-svn-id: http://gnuradio.org/svn/gnuradio/trunk@9362 221aa14e-8319-0410-a670-987f0aec2ac5

1 files changed, 183 insertions, 63 deletions

diff --git a/gr-howto-write-a-block/config/pkg.m4 b/gr-howto-write-a-block/config/pkg.m4
index 770f0629c..80bdfed4c 100644
--- a/gr-howto-write-a-block/config/pkg.m4
+++ b/gr-howto-write-a-block/config/pkg.m4
@@ -1,68 +1,188 @@
-dnl PKG_CHECK_MODULES(GSTUFF, gtk+-2.0 >= 1.3 glib = 1.3.4, action-if, action-not)
-dnl defines GSTUFF_LIBS, GSTUFF_CFLAGS, see pkg-config man page
-dnl also defines GSTUFF_PKG_ERRORS on error
-AC_DEFUN([PKG_CHECK_MODULES], [
-  succeeded=no
-
-  if test -z "$PKG_CONFIG"; then
-    AC_PATH_PROG(PKG_CONFIG, pkg-config, no)
-  fi
-
-  if test "$PKG_CONFIG" = "no" ; then
-     echo "*** The pkg-config script could not be found. Make sure it is"
-     echo "*** in your path, or set the PKG_CONFIG environment variable"
-     echo "*** to the full path to pkg-config."
-     echo "*** Or see http://www.freedesktop.org/software/pkgconfig to get pkg-config."
-  else
-     dnl If PKG_CONFIG_PATH is not already set, add /usr/local/lib/pkgconfig.
-     dnl If it's set, assume the user knows what they're doing.
-     dnl This should help avoid failures while looking for fftw3f
-     if test -z "$PKG_CONFIG_PATH"; then
-	export PKG_CONFIG_PATH="/usr/local/lib/pkgconfig"
-     fi
-
-     PKG_CONFIG_MIN_VERSION=0.9.0
-     if $PKG_CONFIG --atleast-pkgconfig-version $PKG_CONFIG_MIN_VERSION; then
-        AC_MSG_CHECKING(for $2)
-
-        if $PKG_CONFIG --exists "$2" ; then
-            AC_MSG_RESULT(yes)
-            succeeded=yes
-
-            AC_MSG_CHECKING($1_CFLAGS)
-            $1_CFLAGS=`$PKG_CONFIG --cflags "$2"`
-            AC_MSG_RESULT($$1_CFLAGS)
-
-            AC_MSG_CHECKING($1_LIBS)
-            $1_LIBS=`$PKG_CONFIG --libs "$2"`
-            AC_MSG_RESULT($$1_LIBS)
-
-            AC_MSG_CHECKING($1_INCLUDEDIR)
-            $1_INCLUDEDIR=`$PKG_CONFIG --variable=includedir "$2"`
-            AC_MSG_RESULT($$1_INCLUDEDIR)
-        else
-            $1_CFLAGS=""
-            $1_LIBS=""
-            ## If we have a custom action on failure, don't print errors, but 
-            ## do set a variable so people can do so.
-            $1_PKG_ERRORS=`$PKG_CONFIG --errors-to-stdout --print-errors "$2"`
-            ifelse([$4], ,echo $$1_PKG_ERRORS,)
+# pkg.m4 - Macros to locate and utilise pkg-config.            -*- Autoconf -*-
+# 
+# Copyright © 2004 Scott James Remnant <scott@netsplit.com>.
+# Copyright © 2008 Free Software Foundation, Inc.
+#
+# 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, write to the Free Software
+# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+#
+# As a special exception to the GNU General Public License, if you
+# distribute this file as part of a program that contains a
+# configuration script generated by Autoconf, you may include it under
+# the same distribution terms that you use for the rest of that program.
+
+# PKG_PROG_PKG_CONFIG([MIN-VERSION])
+# ----------------------------------
+AC_DEFUN([PKG_PROG_PKG_CONFIG],
+[m4_pattern_forbid([^_?PKG_[A-Z_]+$])
+m4_pattern_allow([^PKG_CONFIG(_PATH)?$])
+AC_ARG_VAR([PKG_CONFIG], [path to pkg-config utility])dnl
+if test "x$ac_cv_env_PKG_CONFIG_set" != "xset"; then
+	AC_PATH_TOOL([PKG_CONFIG], [pkg-config])
+fi
+if test -n "$PKG_CONFIG"; then
+	_pkg_min_version=m4_default([$1], [0.18])
+	AC_MSG_CHECKING([pkg-config is at least version $_pkg_min_version])
+	if $PKG_CONFIG --atleast-pkgconfig-version $_pkg_min_version; then
+		AC_MSG_RESULT([yes])
+	else
+		AC_MSG_RESULT([no])
+		PKG_CONFIG=""
+	fi
+		
+fi[]dnl
+])# PKG_PROG_PKG_CONFIG
+
+# PKG_CHECK_EXISTS(MODULES, [ACTION-IF-FOUND], [ACTION-IF-NOT-FOUND])
+#
+# Check to see whether a particular set of modules exists.  Similar
+# to PKG_CHECK_MODULES(), but does not set variables or print errors.
+#
+#
+# Similar to PKG_CHECK_MODULES, make sure that the first instance of
+# this or PKG_CHECK_MODULES is called, or make sure to call
+# PKG_CHECK_EXISTS manually
+# --------------------------------------------------------------
+AC_DEFUN([PKG_CHECK_EXISTS],
+[AC_REQUIRE([PKG_PROG_PKG_CONFIG])dnl
+if test -n "$PKG_CONFIG" && \
+    AC_RUN_LOG([$PKG_CONFIG --exists --print-errors "$1"]); then
+  m4_ifval([$2], [$2], [:])
+m4_ifvaln([$3], [else
+  $3])dnl
+fi])
+
+
+# _PKG_CONFIG([VARIABLE], [COMMAND], [MODULES])
+# ---------------------------------------------
+m4_define([_PKG_CONFIG],
+[if test -n "$PKG_CONFIG"; then
+    if test -n "$$1"; then
+        pkg_cv_[]$1="$$1"
+    else
+        PKG_CHECK_EXISTS([$3],
+                         [pkg_cv_[]$1=`$PKG_CONFIG --[]$2 "$3" 2>/dev/null`],
+			 [pkg_failed=yes])
+    fi
+else
+	pkg_failed=untried
+fi[]dnl
+])# _PKG_CONFIG
+
+# _PKG_SHORT_ERRORS_SUPPORTED
+# -----------------------------
+AC_DEFUN([_PKG_SHORT_ERRORS_SUPPORTED],
+[AC_REQUIRE([PKG_PROG_PKG_CONFIG])
+if $PKG_CONFIG --atleast-pkgconfig-version 0.20; then
+        _pkg_short_errors_supported=yes
+else
+        _pkg_short_errors_supported=no
+fi[]dnl
+])# _PKG_SHORT_ERRORS_SUPPORTED
+
+
+# PKG_CHECK_MODULES(VARIABLE-PREFIX, MODULES, [ACTION-IF-FOUND],
+# [ACTION-IF-NOT-FOUND])
+#
+# E.g.,
+#   PKG_CHECK_MODULES(GSTUFF, gtk+-2.0 >= 1.3 glib = 1.3.4, action-if, action-not)
+#   defines:
+#
+#     GSTUFF_LIBS
+#     GSTUFF_CFLAGS
+#     GSTUFF_INCLUDEDIR
+#     GSTUFF_CPPFLAGS    # the -I, -D and -U's out of CFLAGS
+#
+# see pkg-config man page also defines GSTUFF_PKG_ERRORS on error
+#
+# Note that if there is a possibility the first call to
+# PKG_CHECK_MODULES might not happen, you should be sure to include an
+# explicit call to PKG_PROG_PKG_CONFIG in your configure.ac
+#
+# --------------------------------------------------------------
+AC_DEFUN([PKG_CHECK_MODULES],
+[AC_REQUIRE([PKG_PROG_PKG_CONFIG])dnl
+AC_ARG_VAR([$1][_CFLAGS], [C compiler flags for $1, overriding pkg-config])dnl
+AC_ARG_VAR([$1][_LIBS], [linker flags for $1, overriding pkg-config])dnl
+AC_ARG_VAR([$1][_INCLUDEDIR], [includedir for $1, overriding pkg-config])dnl
+
+pkg_failed=no
+AC_MSG_CHECKING([for $1])
+
+_PKG_CONFIG([$1][_CFLAGS], [cflags], [$2])
+
+if test x$cross_compiling = xyes
+then
+  _PKG_CONFIG([$1][_LIBS], [libs-only-l --static], [$2])
+else
+  _PKG_CONFIG([$1][_LIBS], [libs --static], [$2])
+fi
+
+_PKG_CONFIG([$1][_INCLUDEDIR], [variable=includedir], [$2])
+
+
+m4_define([_PKG_TEXT], [Alternatively, you may set the environment variables $1[]_CFLAGS
+and $1[]_LIBS to avoid the need to call pkg-config.
+See the pkg-config man page for more details.])
+
+if test $pkg_failed = yes; then
+        _PKG_SHORT_ERRORS_SUPPORTED
+        if test $_pkg_short_errors_supported = yes; then
+	        $1[]_PKG_ERRORS=`$PKG_CONFIG --short-errors --errors-to-stdout --print-errors "$2"`
+        else 
+	        $1[]_PKG_ERRORS=`$PKG_CONFIG --errors-to-stdout --print-errors "$2"`
         fi
+	# Put the nasty error message in config.log where it belongs
+	echo "$$1[]_PKG_ERRORS" >&AS_MESSAGE_LOG_FD
+
+	ifelse([$4], , [AC_MSG_ERROR(dnl
+[Package requirements ($2) were not met:
+
+$$1_PKG_ERRORS
+
+Consider adjusting the PKG_CONFIG_PATH environment variable if you
+installed software in a non-standard prefix.
+
+_PKG_TEXT
+])],
+		[AC_MSG_RESULT([no])
+                $4])
+elif test $pkg_failed = untried; then
+	ifelse([$4], , [AC_MSG_FAILURE(dnl
+[The pkg-config script could not be found or is too old.  Make sure it
+is in your PATH or set the PKG_CONFIG environment variable to the full
+path to pkg-config.
 
-        AC_SUBST($1_CFLAGS)
-        AC_SUBST($1_LIBS)
-        AC_SUBST($1_INCLUDEDIR)
-     else
-        echo "*** Your version of pkg-config is too old. You need version $PKG_CONFIG_MIN_VERSION or newer."
-        echo "*** See http://www.freedesktop.org/software/pkgconfig"
-     fi
-  fi
+_PKG_TEXT
 
-  if test $succeeded = yes; then
-     ifelse([$3], , :, [$3])
-  else
-     ifelse([$4], , AC_MSG_ERROR([Library requirements ($2) not met; consider adjusting the PKG_CONFIG_PATH environment variable if your libraries are in a nonstandard prefix so pkg-config can find them.]), [$4])
-  fi
-])
+To get pkg-config, see <http://pkg-config.freedesktop.org/>.])],
+		[$4])
+else
+	$1[]_CFLAGS=$pkg_cv_[]$1[]_CFLAGS
+	$1[]_LIBS=$pkg_cv_[]$1[]_LIBS
+	$1[]_INCLUDEDIR=$pkg_cv_[]$1[]_INCLUDEDIR
 
+	$1[]_CPPFLAGS=""
+	for flag in $$1[]_CFLAGS; do
+	  case $flag in
+          -I* | -D* | -U*) $1[]_CPPFLAGS="$$1[]_CPPFLAGS $flag" ;;
+          esac
+        done
+	pkg_cv_[]$1[]_CPPFLAGS=$$1[]_CPPFLAGS
+	AC_SUBST($1[]_CPPFLAGS)
 
+        AC_MSG_RESULT([yes])
+	ifelse([$3], , :, [$3])
+fi[]dnl
+])# PKG_CHECK_MODULES