Fix autoheader issues

configure.ac

@@ -146,7 +146,7 @@ dnl Checks for header files.
 AC_HEADER_STDC
 AC_CHECK_HEADERS(time.h)
 AC_CHECK_HEADER(unistd.h,[
-	AC_DEFINE(HAVE_UNISTD_H)
+	AC_DEFINE([HAVE_UNISTD_H], [], [Header unistd.h is available])
 	GD_DEFS="$GD_DEFS -DHAVE_UNISTD_H"
 ])
 
@@ -174,13 +174,13 @@ AC_CHECK_FUNCS(vsnprintf,,check_for_vsnprintf=yes)
 
 if [ test "x$check_for_vsnprintf" = "xyes" ]; then
 	AC_CHECK_FUNC(_vsnprintf,[
-		AC_DEFINE(HAVE_VSNPRINTF)
-		AC_DEFINE(vsnprintf,_vsnprintf)
+		AC_DEFINE([HAVE_VSNPRINTF], [], [Function _vsnprintf is available])
+		AC_DEFINE([vsnprintf], [_vsnprintf], [Use _vsnprintf instead of vsnprintf])
 	],[	dnl Hmm. On the off-chance, check for vsnprintf in libdb.
 		dnl This should, hopefully, solve the problem with Tru64 4.x
 		dnl which is incompatible with trio (the latter's fault).
 		AC_CHECK_LIB(db,vsnprintf,[
-			AC_DEFINE(HAVE_VSNPRINTF)
+			AC_DEFINE([HAVE_VSNPRINTF], [], [Function vsnprintf is available])
 			WMF_LIBFLAGS="$WMF_LIBFLAGS -ldb"
 		],[	require_trio=yes
 		])
@@ -192,8 +192,8 @@ AC_CHECK_FUNCS(snprintf,,check_for_snprintf=yes)
 
 if [ test "x$check_for_snprintf" = "xyes" ]; then
 	AC_CHECK_FUNC(_snprintf,[
-		AC_DEFINE(HAVE_SNPRINTF)
-		AC_DEFINE(snprintf,_snprintf)
+		AC_DEFINE([HAVE_SNPRINTF], [], [Function _snprintf is available])
+		AC_DEFINE([snprintf], [_snprintf], [Use _snprintf instead of snprintf])
 	])
 fi
 
@@ -204,7 +204,7 @@ if [ test "x$check_for_vfscanf" = "xyes" ]; then
 	AC_MSG_CHECKING(for vfscanf in stdio.h)
 	AC_EGREP_HEADER(vfscanf,stdio.h,[
 		AC_MSG_RESULT(yes)
-		AC_DEFINE(HAVE_VFSCANF)
+		AC_DEFINE([HAVE_VFSCANF], [], [Function vfscanf is available])
 	],[	AC_MSG_RESULT(no)
 	])
 fi
@@ -235,7 +235,7 @@ if test $LIBWMF_BUILDSTYLE = lite; then
 fi # $LIBWMF_BUILDSTYLE = lite
 
 if [ test $libwmf_layers = no ]; then
-	AC_DEFINE(WITHOUT_LAYERS,1)
+	AC_DEFINE([WITHOUT_LAYERS], [1], [Don't use layers])
 fi
 
 AM_CONDITIONAL(LIBWMF_OPT_MODULES,[ test $libwmf_layers = modules ])
@@ -361,9 +361,9 @@ if test $libwmf_xml = libxml2 -o $libwmf_xml = unknown; then
 fi
 
 if test $libwmf_xml = expat; then
-	AC_DEFINE(HAVE_EXPAT)
+	AC_DEFINE([HAVE_EXPAT], [], [Use expat as libwmf_xml])
 elif test $libwmf_xml = libxml2; then
-	AC_DEFINE(HAVE_LIBXML2)
+	AC_DEFINE([HAVE_LIBXML2], [], [Use libxml2 as  libwmf_xml])
 else
 	libwmf_xml=none
 	WMF_XML_CFLAGS=""
@@ -524,7 +524,7 @@ AC_CHECK_HEADER(png.h,[
 ],[	AC_MSG_ERROR(* * * unable to find "png.h" which is required by libwmf * * *)
 ])
 
-AC_DEFINE(HAVE_LIBPNG)
+AC_DEFINE([HAVE_LIBPNG], [], [Library libpng is available])
 GD_DEFS="$GD_DEFS -DHAVE_LIBPNG"
 
 fi # $LIBWMF_BUILDSTYLE = heavy
@@ -567,7 +567,7 @@ if [ test "$search_for_jpeg" != "no" ]; then
 			else
 				WMF_JPEG_LDFLAGS="-ljpeg"
 			fi
-			AC_DEFINE(HAVE_LIBJPEG)
+			AC_DEFINE([HAVE_LIBJPEG], [], [Library libjpeg is available])
 			GD_DEFS="$GD_DEFS -DHAVE_LIBJPEG"
 			libwmf_gd_jpeg=yes
 		])
@@ -649,7 +649,7 @@ if [ test "$search_for_gd" != "no" ]; then
 fi
 
 if [ test "x$libwmf_gd" != "xnone" ]; then
-	AC_DEFINE(HAVE_GD,1)
+	AC_DEFINE([HAVE_GD], [1], [Library gd is available])
 	build_gd_layer=yes
 else
 	build_gd_layer=no
@@ -711,7 +711,7 @@ if [ test "$search_for_plot" != "no" ]; then
 				else
 					WMF_PLOT_LDFLAGS="$LIBPLOT_LIBS"
 				fi
-				AC_DEFINE(HAVE_LIBPLOT)
+				AC_DEFINE([HAVE_LIBPLOT], [], [Library libplot is available])
 				libwmf_plot=maybe
 			else
 				AC_MSG_ERROR(* * * sorry - unable to link against libplot * * *)