Add pkgconfig support to libassuan.
This patch is rejected by upstream for the reason below:
They think pkgconfig adds no portability and maintaining them is not worthwhile.

Upstream-Status: Denied
Signed-off-by: Chen Qi <Qi.Chen@windriver.com>
Signed-off-by: Constantin Musca <constantinx.musca@intel.com>

Index: libassuan-2.1.2/Makefile.am
===================================================================
--- libassuan-2.1.2.orig/Makefile.am
+++ libassuan-2.1.2/Makefile.am
@@ -24,10 +24,13 @@ AUTOMAKE_OPTIONS = dist-bzip2 no-dist-gz
 # (A suitable gitlog-to-changelog script can be found in GnuPG master.)
 GITLOG_TO_CHANGELOG=gitlog-to-changelog
 
+pkgconfigdir = $(libdir)/pkgconfig
+pkgconfig_DATA = libassuan.pc
+
 EXTRA_DIST = autogen.sh autogen.rc README.GIT         	                \
              ChangeLog-2011 doc/ChangeLog-2011 src/ChangeLog-2011 	\
              tests/ChangeLog-2011 contrib/ChangeLog-2011     		\
-             build-aux/git-log-footer build-aux/git-log-fix
+             build-aux/git-log-footer build-aux/git-log-fix libassuan.pc.in
 
 SUBDIRS = m4 src doc tests
 
Index: libassuan-2.1.2/libassuan.pc.in
===================================================================
--- /dev/null
+++ libassuan-2.1.2/libassuan.pc.in
@@ -0,0 +1,14 @@
+prefix=@prefix@
+exec_prefix=@exec_prefix@
+libdir=@libdir@
+includedir=@includedir@
+api_version=@LIBASSUAN_CONFIG_API_VERSION@
+host=@LIBASSUAN_CONFIG_HOST@
+
+Name: libassuan
+Description: IPC library used by GnuPG and GPGME
+Requires:
+Version: @VERSION@
+Libs: -L${libdir} -lassuan
+Libs.private: -lgpg-error
+Cflags: -I${includedir}
Index: libassuan-2.1.2/configure.ac
===================================================================
--- libassuan-2.1.2.orig/configure.ac
+++ libassuan-2.1.2/configure.ac
@@ -439,7 +439,7 @@ AC_CONFIG_FILES([doc/Makefile])
 AC_CONFIG_FILES([tests/Makefile])
 AC_CONFIG_FILES([src/libassuan-config], [chmod +x src/libassuan-config])
 AC_CONFIG_FILES([src/versioninfo.rc])
-
+AC_CONFIG_FILES([libassuan.pc])
 AC_OUTPUT
 
 echo "
Index: libassuan-2.1.2/src/libassuan.m4
===================================================================
--- libassuan-2.1.2.orig/src/libassuan.m4
+++ libassuan-2.1.2/src/libassuan.m4
@@ -15,18 +15,6 @@ dnl Returns ok set to yes or no.
 dnl
 AC_DEFUN([_AM_PATH_LIBASSUAN_COMMON],
 [ AC_REQUIRE([AC_CANONICAL_HOST])
-  AC_ARG_WITH(libassuan-prefix,
-              AC_HELP_STRING([--with-libassuan-prefix=PFX],
-                             [prefix where LIBASSUAN is installed (optional)]),
-     libassuan_config_prefix="$withval", libassuan_config_prefix="")
-  if test x$libassuan_config_prefix != x ; then
-    libassuan_config_args="$libassuan_config_args --prefix=$libassuan_config_prefix"
-    if test x${LIBASSUAN_CONFIG+set} != xset ; then
-      LIBASSUAN_CONFIG=$libassuan_config_prefix/bin/libassuan-config
-    fi
-  fi
-
-  AC_PATH_TOOL(LIBASSUAN_CONFIG, libassuan-config, no)
 
   tmp=ifelse([$1], ,1:0.9.2,$1)
   if echo "$tmp" | grep ':' >/dev/null 2>/dev/null ; then
@@ -37,51 +25,12 @@ AC_DEFUN([_AM_PATH_LIBASSUAN_COMMON],
     min_libassuan_version="$tmp"
   fi
 
-  AC_MSG_CHECKING(for LIBASSUAN - version >= $min_libassuan_version)
-  ok=no
-  if test "$LIBASSUAN_CONFIG" != "no" \
-     && test -f "$LIBASSUAN_CONFIG" ; then
-    req_major=`echo $min_libassuan_version | \
-               sed 's/\([[0-9]]*\)\.\([[0-9]]*\)\.\([[0-9]]*\)/\1/'`
-    req_minor=`echo $min_libassuan_version | \
-               sed 's/\([[0-9]]*\)\.\([[0-9]]*\)\.\([[0-9]]*\)/\2/'`
-    req_micro=`echo $min_libassuan_version | \
-               sed 's/\([[0-9]]*\)\.\([[0-9]]*\)\.\([[0-9]]*\)/\3/'`
-
-    libassuan_config_version=`$LIBASSUAN_CONFIG --version`
-    major=`echo $libassuan_config_version | \
-               sed 's/\([[0-9]]*\)\.\([[0-9]]*\)\.\([[0-9]]*\).*/\1/'`
-    minor=`echo $libassuan_config_version | \
-               sed 's/\([[0-9]]*\)\.\([[0-9]]*\)\.\([[0-9]]*\).*/\2/'`
-    micro=`echo $libassuan_config_version | \
-               sed 's/\([[0-9]]*\)\.\([[0-9]]*\)\.\([[0-9]]*\).*/\3/'`
-
-    if test "$major" -gt "$req_major"; then
-        ok=yes
-    else 
-        if test "$major" -eq "$req_major"; then
-            if test "$minor" -gt "$req_minor"; then
-               ok=yes
-            else
-               if test "$minor" -eq "$req_minor"; then
-                   if test "$micro" -ge "$req_micro"; then
-                     ok=yes
-                   fi
-               fi
-            fi
-        fi
-    fi
-  fi
-
-  if test $ok = yes; then
-    AC_MSG_RESULT([yes ($libassuan_config_version)])
-  else
-    AC_MSG_RESULT(no)
-  fi
+  PKG_CHECK_MODULES(LIBASSUAN, [libassuan >= $min_libassuan_version], [ok=yes], [ok=no])
 
   if test $ok = yes; then
     if test "$req_libassuan_api" -gt 0 ; then
       tmp=`$LIBASSUAN_CONFIG --api-version 2>/dev/null || echo 0`
+      tmp=`$PKG_CONFIG --variable=api_version libassuan`
       if test "$tmp" -gt 0 ; then
         AC_MSG_CHECKING([LIBASSUAN API version])
         if test "$req_libassuan_api" -eq "$tmp" ; then
@@ -96,7 +45,7 @@ AC_DEFUN([_AM_PATH_LIBASSUAN_COMMON],
 
   if test $ok = yes; then
     if test x"$host" != x ; then
-      libassuan_config_host=`$LIBASSUAN_CONFIG --host 2>/dev/null || echo none`
+      libassuan_config_host=`$PKG_CONFIG --variable=host libassuan`
       if test x"$libassuan_config_host" != xnone ; then
         if test x"$libassuan_config_host" != x"$host" ; then
   AC_MSG_WARN([[
@@ -137,12 +86,8 @@ dnl
 AC_DEFUN([AM_PATH_LIBASSUAN],
 [ _AM_PATH_LIBASSUAN_COMMON($1)
   if test $ok = yes; then
-    LIBASSUAN_CFLAGS=`$LIBASSUAN_CONFIG $libassuan_config_args --cflags`
-    LIBASSUAN_LIBS=`$LIBASSUAN_CONFIG $libassuan_config_args --libs`
     ifelse([$2], , :, [$2])
   else
-    LIBASSUAN_CFLAGS=""
-    LIBASSUAN_LIBS=""
     ifelse([$3], , :, [$3])
   fi
   AC_SUBST(LIBASSUAN_CFLAGS)