Index: m4macros/xdt-features.m4
===================================================================
--- m4macros/xdt-features.m4	(revision 25298)
+++ m4macros/xdt-features.m4	(working copy)
@@ -32,39 +32,159 @@
 
 
 
-dnl XDT_FEATURE_DEBUG()
+dnl _XDT_FEATURE_DEBUG()
 dnl
-AC_DEFUN([XDT_FEATURE_DEBUG],
+AC_DEFUN([_XDT_FEATURE_DEBUG],
 [
   AC_ARG_ENABLE([debug],
-AC_HELP_STRING([--enable-debug[=yes|no|full]], [Build with debugging support])
-AC_HELP_STRING([--disable-debug], [Include no debugging support [default]]),
-  [], [enable_debug=no])
+  AC_HELP_STRING([--enable-debug=@<:@no/minimum/yes/full@:>@], [Turn on debugging @<:@default=xdt_cv_debug_default@:>@]),
+    [], [enable_debug=xdt_cv_debug_default])
+  AC_MSG_CHECKING([whether to enable debugging support])
+  if test x"$enable_debug" = x"full" -o x"$enable_debug" = x"yes"; then
+    dnl Print the result
+    AC_MSG_RESULT([$enable_debug])
 
-  AC_MSG_CHECKING([whether to build with debugging support])
-  if test x"$enable_debug" != x"no"; then
-    AC_DEFINE([DEBUG], [1], [Define for debugging support])
+    dnl Check whether the compiler accepts the -errwarn=%all
+    dnl (Support for the Solaris CC compiler)
+    save_CFLAGS="$CFLAGS"
+    CFLAGS="$CFLAGS -errwarn=%all"
+    AC_MSG_CHECKING([whether $CC accepts -errwarn=%all])
+    AC_COMPILE_IFELSE(AC_LANG_SOURCE([int x;]), [
+      AC_MSG_RESULT([yes])
+      xdt_cv_additional_CFLAGS="$xdt_cv_additional_CFLAGS -errwarn=%all"
+    ], [
+      AC_MSG_RESULT([no])
+    ])
+    CFLAGS="$save_CFLAGS"
 
-    if test x"$GCC" = x"yes"; then
-      xdt_cv_additional_CFLAGS="-Wall"
-    fi
-    xdt_cv_additional_CFLAGS="$xdt_cv_additional_CFLAGS -DXFCE_DISABLE_DEPRECATED"
+    dnl Make sure we detect possible errors (if supported)
+    save_CFLAGS="$CFLAGS"
+    CFLAGS="$CFLAGS -Wall -Werror"
+    AC_MSG_CHECKING([whether $CC accepts -Wall -Werror])
+    AC_COMPILE_IFELSE(AC_LANG_SOURCE([int x;]), [
+      AC_MSG_RESULT([yes])
+      xdt_cv_additional_CFLAGS="$xdt_cv_additional_CFLAGS -Wall -Werror"
+    ], [
+      AC_MSG_RESULT([no])
+    ])
+    CFLAGS="$save_CFLAGS"
     
+    dnl Check whether the compiler accepts the -fno-strict-aliasing
+    save_CFLAGS="$CFLAGS"
+    CFLAGS="$CFLAGS -fno-strict-aliasing"
+    AC_MSG_CHECKING([whether $CC accepts -fno-strict-aliasing])
+    AC_COMPILE_IFELSE(AC_LANG_SOURCE([int x;]), [
+      AC_MSG_RESULT([yes])
+      xdt_cv_additional_CFLAGS="$xdt_cv_additional_CFLAGS -fno-strict-aliasing"
+    ], [
+      AC_MSG_RESULT([no])
+    ])
+    CFLAGS="$save_CFLAGS"
+
+    dnl Paranoia for --enable-debug=full
     if test x"$enable_debug" = x"full"; then
-      AC_DEFINE([DEBUG_TRACE], [1], [Define for tracing support])
-      if test x"$GCC" = x"yes"; then
-        xdt_cv_additional_CFLAGS="-g3 -Werror $xdt_cv_additional_CFLAGS"
-      fi
-      AC_MSG_RESULT([full])
-    else
-      if test x"$GCC" = x"yes"; then
-        xdt_cv_additional_CFLAGS="-g $xdt_cv_additional_CFLAGS"
-      fi
-      AC_MSG_RESULT([yes])
+      dnl Enable extensive debugging
+      xdt_cv_additional_CPPFLAGS="$xdt_cv_additional_CPPFLAGS -DG_ENABLE_DEBUG"
+
+      dnl Use -O0 -g3 if the compiler supports it
+      save_CFLAGS="$CFLAGS"
+      CFLAGS="$CFLAGS -O0 -g3"
+      AC_MSG_CHECKING([whether $CC accepts -O0 -g3])
+      AC_COMPILE_IFELSE(AC_LANG_SOURCE([int x;]), [
+        AC_MSG_RESULT([yes])
+        xdt_cv_additional_CFLAGS="$xdt_cv_additional_CFLAGS -O0 -g3"
+      ], [
+        AC_MSG_RESULT([no])
+      ])
+      CFLAGS="$save_CFLAGS"
     fi
+  else
+    dnl Print the result
+    AC_MSG_RESULT([$enable_debug])
 
-    CFLAGS="$CFLAGS $xdt_cv_additional_CFLAGS"
-    CXXFLAGS="$CXXFLAGS $xdt_cv_additional_CFLAGS"
+    dnl Disable debugging (release build)
+    xdt_cv_additional_CPPFLAGS="$xdt_cv_additional_CPPFLAGS -DNDEBUG"
+
+    dnl Disable object cast checks
+    xdt_cv_additional_CPPFLAGS="$xdt_cv_additional_CPPFLAGS -DG_DISABLE_CAST_CHECKS"
+
+    dnl Disable all checks for --enable-debug=no
+    if test x"$enable_debug" = x"no"; then
+      xdt_cv_additional_CPPFLAGS="$xdt_cv_additional_CPPFLAGS -DG_DISABLE_ASSERT -DG_DISABLE_CHECKS"
+    fi
+  fi
+])
+
+
+
+dnl XDT_FEATURE_DEBUG()
+dnl
+AC_DEFUN([XDT_FEATURE_DEBUG],
+[
+  dnl Check if a default debug mode is set
+  m4_define([xdt_cv_debug_default], [ifelse([$1], [], [minimum], [$1])])
+  
+  dnl Check for debugging
+  AC_REQUIRE([_XDT_FEATURE_DEBUG])
+  
+  dnl Set the flags
+  CFLAGS="$CFLAGS $xdt_cv_additional_CFLAGS $xdt_cv_additional_CPPFLAGS"
+  CXXFLAGS="$CXXFLAGS $xdt_cv_additional_CFLAGS $xdt_cv_additional_CPPFLAGS"
+])
+
+
+
+dnl XDT_FEATURE_DEBUG_PLATFORM()
+dnl
+AC_DEFUN([XDT_FEATURE_DEBUG_PLATFORM],
+[
+  dnl Check if a default debug mode is set
+  m4_define([xdt_cv_debug_default], [ifelse([$1], [], [minimum], [$1])])
+    
+  dnl Check for debugging
+  AC_REQUIRE([_XDT_FEATURE_DEBUG])
+  
+  dnl Set the platform flags
+  PLATFORM_CPPFLAGS="$PLATFORM_CPPFLAGS $xdt_cv_additional_CPPFLAGS"
+  PLATFORM_CFLAGS="$PLATFORM_CFLAGS $xdt_cv_additional_CFLAGS"
+])
+
+
+
+dnl XDT_FEATURE_LINKER()
+dnl
+AC_DEFUN([XDT_FEATURE_LINKER],
+[
+  AC_REQUIRE([AC_PROG_LD])
+  AC_ARG_ENABLE([final],
+  AC_HELP_STRING([--enable-final], [Build final version (enable linker optimizations)]),
+    [], [enable_final=yes])
+
+  AC_MSG_CHECKING([whether to build final version])
+  if test x"$enable_final" = x"yes"; then
+    AC_MSG_RESULT([yes])
+    
+    AC_MSG_CHECKING([whether $LD accepts --as-needed])
+    case `$LD --as-needed -v 2>&1 </dev/null` in
+      *GNU* | *'with BFD'*)
+        LDFLAGS="$LDFLAGS -Wl,--as-needed"
+        AC_MSG_RESULT([yes])
+        ;;
+      *)
+        AC_MSG_RESULT([no])
+        ;;
+    esac
+
+    AC_MSG_CHECKING([whether $LD accepts -O1])
+    case `$LD -O1 -v 2>&1 </dev/null` in
+      *GNU* | *'with BFD'*)
+        LDFLAGS="$LDFLAGS -Wl,-O1"
+        AC_MSG_RESULT([yes])
+        ;;
+      *)
+        AC_MSG_RESULT([no])
+        ;;
+    esac
   else
     AC_MSG_RESULT([no])
   fi
@@ -72,6 +192,39 @@
 
 
 
+dnl XDT_FEATURE_VISIBILITY()
+dnl
+AC_DEFUN([XDT_FEATURE_VISIBILITY],
+[
+  AC_ARG_ENABLE([visibility], AC_HELP_STRING([--disable-visibility], [Don't use ELF visibility attributes]), [], [enable_visibility=yes])
+  have_gnuc_visibility=no
+  if test x"$enable_visibility" != x"no"; then
+    dnl Check whether the compiler supports the visibility attribute
+    save_CFLAGS="$CFLAGS"
+    CFLAGS="$CFLAGS -Wall -Werror"
+    AC_MSG_CHECKING([whether $CC supports the GNUC visibility attribute])
+    AC_COMPILE_IFELSE(AC_LANG_SOURCE(
+    [
+      void __attribute__ ((visibility("default"))) test_default (void) {}
+      void __attribute__ ((visibility("hidden"))) test_hidden (void) {}
+      int main (int argc, char **argv) { test_default (); test_hidden (); return 0; }
+    ]),
+    [
+      have_gnuc_visibility=yes
+      AC_MSG_RESULT([yes])
+    ],
+    [
+      AC_MSG_RESULT([no])
+    ])
+    CFLAGS="$save_CFLAGS"
+  fi
+  if test x"$have_gnuc_visibility" = x"yes"; then
+    PLATFORM_CPPFLAGS="$PLATFORM_CPPFLAGS -DHAVE_GNUC_VISIBILITY"
+  fi
+  AM_CONDITIONAL([HAVE_GNUC_VISIBILITY], [test x"$have_gnuc_visibility" = x"yes"])
+])
+
+
 dnl BM_DEBUG_SUPPORT()
 dnl
 AC_DEFUN([BM_DEBUG_SUPPORT],
@@ -127,25 +280,5 @@
   fi
 
 dnl # --enable-final
-  AC_REQUIRE([AC_PROG_LD])
-  AC_ARG_ENABLE([final],
-AC_HELP_STRING([--enable-final], [Build final version]),
-    [], [enable_final=yes])
-
-  AC_MSG_CHECKING([whether to build final version])
-  if test x"$enable_final" = x"yes"; then
-    AC_MSG_RESULT([yes])
-    AC_MSG_CHECKING([whether $LD accepts -O1])
-    case `$LD -O1 -v 2>&1 </dev/null` in
-    *GNU* | *'with BFD'*)
-      LDFLAGS="$LDFLAGS -Wl,-O1"
-      AC_MSG_RESULT([yes])
-    	;;
-    *)
-      AC_MSG_RESULT([no])
-    	;;
-    esac
-  else
-    AC_MSG_RESULT([no])
-  fi
+  AC_REQUIRE([XDT_FEATURE_LINKER])
 ])