Update configure.ac and a few macros used by it

The changes done to configure.ac are essentially divided in two categories:
the first is made of changes to improve existing checks, even if it's merely
in the message being printed during the check; the second category is made of
updates aimed at bringing this file closer to Autoconf 2.71, which deprecated
or even removed some stuff that was otherwise present either directly in
configure.ac or in one of the macros it includes, which have been updated in
this commit too.

Actually, the generated configure script was created by Autoconf 2.71 during
deveopment, so in a way it's already compatible with the latest version.

1 files changed, 12 insertions, 23 deletions

diff --git a/m4/check-libheader.m4 b/m4/check-libheader.m4
index 1e24d8a97..4e0285336 100644
--- a/m4/check-libheader.m4
+++ b/m4/check-libheader.m4
@@ -11,30 +11,19 @@ dnl HEADER-NAME         - header file name as in AC_CHECK_HEADER
 dnl ACTION-IF-FOUND     - when feature is found then execute given action
 dnl ACTION-IF-NOT-FOUND - when feature is not found then execute given action
 dnl EXTRA-LDFLAGS       - extra linker flags (-L or -l)
-dnl EXTRA-CPPFLAGS      - extra C preprocessor flags, i.e. -I/usr/X11R6/include
+dnl EXTRA-CPPFLAGS      - extra C preprocessor flags, e.g. -I/usr/X11R6/include
 dnl
-dnl Based on GST_CHECK_LIBHEADER from gstreamer plugins 0.3.1.
 dnl
 AC_DEFUN([CHECK_LIBHEADER],
-[
-  AC_CHECK_LIB([$2], [$3], HAVE_[$1]=yes, HAVE_[$1]=no, [$7])
-  check_libheader_feature_name=translit([$1], A-Z, a-z)
-
-  if test "x$HAVE_[$1]" = "xyes"; then
-    check_libheader_save_CPPFLAGS=$CPPFLAGS
-    CPPFLAGS="[$8] $CPPFLAGS"
-    AC_CHECK_HEADER([$4], :, HAVE_[$1]=no)
-    CPPFLAGS=$check_libheader_save_CPPFLAGS
-  fi
-
-  if test "x$HAVE_[$1]" = "xyes"; then
-    ifelse([$5], , :, [$5])
-    AC_MSG_NOTICE($check_libheader_feature_name was found)
-  else
-    ifelse([$6], , :, [$6])
-    AC_MSG_WARN($check_libheader_feature_name not found)
-  fi
-  AC_SUBST(HAVE_[$1])
-]
-)
+[m4_if([$7], ,:,[LDFLAGS="$7 $LDFLAGS"])
+ m4_if([$8], ,:,[CPPFLAGS="$8 $CPPFLAGS"])
 
+ AC_CHECK_HEADERS([$4],
+   [AC_CHECK_LIB([$2], [$3],
+      [eval "HAVE_]AS_TR_SH([$1])[=yes"]
+       m4_if([$5], ,:,[$5]),
+      [eval "HAVE_]AS_TR_SH([$1])[=no"]
+       m4_if([$6], ,:,[$6]))],
+   [eval "HAVE_]AS_TR_SH([$1])[=no"]
+    m4_if([$6], ,:,[$6]))
+])dnl