dnl GNOME_COMPILE_WARNINGS
dnl Turn on many useful compiler warnings
dnl For now, only works on GCC
AC_DEFUN([GNOME_COMPILE_WARNINGS],[
  AC_ARG_ENABLE(compile-warnings, 
    [  --enable-compile-warnings=[no/minimum/yes]	Turn on compiler warnings.],,enable_compile_warnings=minimum)

  AC_MSG_CHECKING(what warning flags to pass to the C compiler)
  warnCFLAGS=
  if test "x$GCC" != xyes; then
    enable_compile_warnings=no
  fi

  if test "x$enable_compile_warnings" != "xno"; then
    if test "x$GCC" = "xyes"; then
      case " $CFLAGS " in
      *[\ \	]-Wall[\ \	]*) ;;
      *) warnCFLAGS="-Wall -Wno-unused" ;;
      esac

      ## -W is not all that useful.  And it cannot be controlled
      ## with individual -Wno-xxx flags, unlike -Wall
      if test "x$enable_compile_warnings" = "xyes"; then
	warnCFLAGS="$warnCFLAGS -Wmissing-prototypes -Wmissing-declarations -Wpointer-arith"
      fi
    fi
  fi
  AC_MSG_RESULT($warnCFLAGS)

  AC_ARG_ENABLE(iso-c,
    [  --enable-iso-c          Try to warn if code is not ISO C ],,
    enable_iso_c=no)

  AC_MSG_CHECKING(what language compliance flags to pass to the C compiler)
  complCFLAGS=
  if test "x$enable_iso_c" != "xno"; then
    if test "x$GCC" = "xyes"; then
      case " $CFLAGS " in
      *[\ \	]-ansi[\ \	]*) ;;
      *) complCFLAGS="$complCFLAGS -ansi" ;;
      esac

      case " $CFLAGS " in
      *[\ \	]-pedantic[\ \	]*) ;;
      *) complCFLAGS="$complCFLAGS -pedantic" ;;
      esac
    fi
  fi
  AC_MSG_RESULT($complCFLAGS)
  if test "x$cflags_set" != "xyes"; then
    CFLAGS="$CFLAGS $warnCFLAGS $complCFLAGS"
    cflags_set=yes
    AC_SUBST(cflags_set)
  fi
])

dnl For C++, do basically the same thing.

AC_DEFUN([GNOME_CXX_WARNINGS],[
  AC_ARG_ENABLE(cxx-warnings, 
    [  --enable-cxx-warnings=[no/minimum/yes]	Turn on compiler warnings.],,enable_cxx_warnings=minimum)

  AC_MSG_CHECKING(what warning flags to pass to the C++ compiler)
  warnCXXFLAGS=
  if test "x$GCC" != xyes; then
    enable_compile_warnings=no
  fi
  if test "x$enable_cxx_warnings" != "xno"; then
    if test "x$GCC" = "xyes"; then
      case " $CXXFLAGS " in
      *[\ \	]-Wall[\ \	]*) ;;
      *) warnCXXFLAGS="-Wall -Wno-unused" ;;
      esac

      ## -W is not all that useful.  And it cannot be controlled
      ## with individual -Wno-xxx flags, unlike -Wall
      if test "x$enable_cxx_warnings" = "xyes"; then
	warnCXXFLAGS="$warnCXXFLAGS -Wmissing-prototypes -Wmissing-declarations -Wpointer-arith -Wshadow -Woverloaded-virtual"
      fi
    fi
  fi
  AC_MSG_RESULT($warnCXXFLAGS)

   AC_ARG_ENABLE(iso-cxx,
     [  --enable-iso-cxx          Try to warn if code is not ISO C++ ],,
     enable_iso_cxx=no)

   AC_MSG_CHECKING(what language compliance flags to pass to the C++ compiler)
   complCXXFLAGS=
   if test "x$enable_iso_cxx" != "xno"; then
     if test "x$GCC" = "xyes"; then
      case " $CXXFLAGS " in
      *[\ \	]-ansi[\ \	]*) ;;
      *) complCXXFLAGS="$complCXXFLAGS -ansi" ;;
      esac

      case " $CXXFLAGS " in
      *[\ \	]-pedantic[\ \	]*) ;;
      *) complCXXFLAGS="$complCXXFLAGS -pedantic" ;;
      esac
     fi
   fi
  AC_MSG_RESULT($complCXXFLAGS)
  if test "x$cxxflags_set" != "xyes"; then
    CXXFLAGS="$CXXFLAGS $warnCXXFLAGS $complCXXFLAGS"
    cxxflags_set=yes
    AC_SUBST(cxxflags_set)
  fi
])