Configure: Rewrite the detection for Pango library

Make use of the standard macro for PKG_CONFIG; the default behaviour is now
to use Pango if present, instead of requiring explicit user request, yet
still not making it mandatory.

The detection code was moved to a macro to keep the configure.ac script
(relatively) small, and consistent with what is done for most other libs.

Signed-off-by: Christophe CURIS <christophe.curis@free.fr>

WINGs/Makefile.am

@@ -12,7 +12,7 @@ lib_LTLIBRARIES = libWUtil.la libWINGs.la
 
 
 LDADD= libWUtil.la libWINGs.la $(top_builddir)/wrlib/libwraster.la @INTLIBS@
-libWINGs_la_LIBADD = libWUtil.la $(top_builddir)/wrlib/libwraster.la @XLIBS@ @XFT_LIBS@ @FCLIBS@ @LIBM@ @PANGOLIBS@
+libWINGs_la_LIBADD = libWUtil.la $(top_builddir)/wrlib/libwraster.la @XLIBS@ @XFT_LIBS@ @FCLIBS@ @LIBM@ @PANGO_LIBS@
 libWUtil_la_LIBADD = @LIBBSD@
 
 EXTRA_DIST = BUGS make-rgb Examples Extras Tests
@@ -87,7 +87,7 @@ libWUtil_la_SOURCES = 	\
 	wutil.c
 
 
-AM_CFLAGS =
+AM_CFLAGS = @PANGO_CFLAGS@
 
 AM_CPPFLAGS = -DRESOURCE_PATH=\"$(datadir)/WINGs\" \
 	 -I$(top_srcdir)/WINGs/WINGs -I$(top_builddir)/WINGs/WINGs \

configure.ac

@@ -636,24 +636,15 @@ AC_SUBST(XFT_LIBS)
 
 dnl PANGO support
 dnl =============
-pango=no
-AC_ARG_ENABLE(pango, AS_HELP_STRING([--enable-pango], [enable Pango text layout support]),
-                pango=$enableval, pango=no)
+dnl The libray can be used by WINGs to get better support on UTF-8 for i18n
+AC_ARG_ENABLE([pango],
+    [AS_HELP_STRING([--disable-pango], [disable Pango text layout support @<:@default=auto@:>@])],
+    [AS_CASE([$enableval],
+        [yes|no], [],
+        [AC_MSG_ERROR([bad value $enableval for --disable-pango])] )],
+    [enable_pango=auto])
+WM_CHECK_LIBPANGO
 
-PANGOFLAGS=
-PANGOLIBS=
-if test "$pango" = yes; then
-	PANGOLIBS=`$PKG_CONFIG pangoxft --libs`
-	PANGOFLAGS=`$PKG_CONFIG pangoxft --cflags`
-	if test "x$PANGOLIBS" = "x" ; then
-	        AC_MSG_RESULT([not found])
-	else
-		AC_DEFINE(USE_PANGO, 1, [Define if Pango is to be used])
-		AC_MSG_RESULT([found])
-	fi
-fi
-inc_search_path="$inc_search_path $PANGOFLAGS"
-AC_SUBST(PANGOLIBS)
 
 dnl ==============================================
 dnl         Graphic Format Libraries

doc/build/Compilation.texi

@@ -224,7 +224,7 @@ Get the @emph{GNU} version from @uref{http://www.gnu.org/software/gettext/}
 
 This library can be used by the @emph{WINGs} toolkit to improve support for @emph{UTF-8} and for
 languages written in right-to-left direction, in some widgets.
-You have to explicitly ask for its support through (@pxref{Configure Options}).
+If detected, it will be automatically used; you may request explicit support/ignore through (@pxref{Configure Options}).
 You can get it from @uref{http://www.pango.org/Download}
 
 @item @emph{libbsd}
@@ -484,8 +484,8 @@ even if your system provides it.
 @item --disable-magick
 Disable @emph{ImageMagick's MagickWand} support in @emph{WRaster}, used to support for image formats.
 
-@item --enable-pango
-Disabled by default, enable @emph{Pango} text layout support in @emph{WINGs}.
+@item --disable-pango
+Disable @emph{Pango} text layout support in @emph{WINGs}.
 
 @item --disable-png
 Disable PNG support in @emph{WRaster}; when enabled use @file{libpng}.

m4/windowmaker.m4

@@ -50,6 +50,27 @@ AC_DEFUN([WM_CHECK_XFT_VERSION],
 ])
 
 
+# WM_CHECK_LIBPANGO
+# -----------------
+#
+# If the support was not disabled by user, check for the pango library using
+# pkg-config, and if found place the appropriate stuff in the variables
+# PANGO_CFLAGS (for compiler) and PANGO_LIBS (for linker)
+AC_DEFUN([WM_CHECK_LIBPANGO],
+[AS_IF([test "x$enable_pango" != "xno"],
+    [PKG_CHECK_MODULES([PANGO], [pangoxft],
+        [AC_DEFINE([USE_PANGO], [1], [defined when the pango library is used in WINGs])
+         pango="yes"],
+        [pango="no"])
+     AS_IF([test "x$enable_pango$pango" == "xyesno"],
+        [AC_MSG_ERROR([Pango library was not found - $PANGO_PKG_ERRORS])])
+    ],
+    [pango="no"])
+ AC_SUBST([PANGO_CFLAGS])dnl
+ AC_SUBST([PANGO_LIBS])dnl
+])
+
+
 # _WM_LIB_CHECK_FUNCTS
 # --------------------
 # (internal shell functions)