File aclocal/shobj.m4 artifact 2c7adb586d part of check-in 7781365c5e

dnl Usage:
dnl    DC_TEST_SHOBJFLAGS(shobjflags, shobjldflags, action-if-not-found)
dnl
AC_DEFUN(DC_TEST_SHOBJFLAGS, [
  AC_SUBST(SHOBJFLAGS)
  AC_SUBST(SHOBJLDFLAGS)

  OLD_LDFLAGS="$LDFLAGS"
  SHOBJFLAGS=""

  LDFLAGS="$OLD_LDFLAGS $1 $2"

  AC_TRY_LINK([#include <stdio.h>
int unrestst(void);], [ printf("okay\n"); unrestst(); return(0); ], [ SHOBJFLAGS="$1"; SHOBJLDFLAGS="$2" ], [
  LDFLAGS="$OLD_LDFLAGS"
  $3
])

  LDFLAGS="$OLD_LDFLAGS"
])

AC_DEFUN(DC_GET_SHOBJFLAGS, [
  AC_SUBST(SHOBJFLAGS)
  AC_SUBST(SHOBJLDFLAGS)

  AC_MSG_CHECKING(how to create shared objects)

  if test -z "$SHOBJFLAGS" -a -z "$SHOBJLDFLAGS"; then
    DC_TEST_SHOBJFLAGS([-fPIC -DPIC], [-shared -rdynamic], [
      DC_TEST_SHOBJFLAGS([-fPIC -DPIC], [-shared], [
        DC_TEST_SHOBJFLAGS([-fPIC -DPIC], [-shared -rdynamic -mimpure-text], [
          DC_TEST_SHOBJFLAGS([-fPIC -DPIC], [-shared -mimpure-text], [
            DC_TEST_SHOBJFLAGS([-fPIC -DPIC], [-shared -rdynamic -Wl,-G,-z,textoff], [
              DC_TEST_SHOBJFLAGS([-fPIC -DPIC], [-shared -Wl,-G,-z,textoff], [
                DC_TEST_SHOBJFLAGS([-fPIC -DPIC], [-shared -dynamiclib -flat_namespace -undefined suppress -bind_at_load], [
                  DC_TEST_SHOBJFLAGS([-fPIC -DPIC], [-dynamiclib -flat_namespace -undefined suppress -bind_at_load], [
                    DC_TEST_SHOBJFLAGS([-fPIC -DPIC], [-Wl,-dynamiclib -Wl,-flat_namespace -Wl,-undefined,suppress -Wl,-bind_at_load], [
                      DC_TEST_SHOBJFLAGS([-fPIC -DPIC], [-dynamiclib -flat_namespace -undefined suppress], [
                        DC_TEST_SHOBJFLAGS([-fPIC -DPIC], [-dynamiclib], [
                          AC_MSG_RESULT(cant)
                          AC_MSG_ERROR([We are unable to make shared objects.])
                        ])
                      ])
                    ])
                  ])
                ])
              ])
            ])
          ])
        ])
      ])
    ])
  fi

  AC_MSG_RESULT($SHOBJLDFLAGS $SHOBJFLAGS)
])

AC_DEFUN(DC_CHK_OS_INFO, [
	AC_CANONICAL_HOST
	AC_SUBST(SHOBJEXT)
	AC_SUBST(AREXT)
        AC_SUBST(SHOBJFLAGS)
        AC_SUBST(SHOBJLDFLAGS)

        AC_MSG_CHECKING(host operating system)
        AC_MSG_RESULT($host_os)

	SHOBJEXT="so"
	AREXT="a"

        case $host_os in
                darwin*)
			SHOBJEXT="dylib"
                        ;;
		hpux*)
			SHOBJEXT="sl"
			;;
		mingw*)
			SHOBJEXT="dll"
			SHOBJFLAGS="-mms-bitfields -DPIC"
			SHOBJLDFLAGS='-shared -Wl,--dll -Wl,--enable-auto-image-base -Wl,--output-def,$[@].def,--out-implib,$[@].a'
			;;
	esac
])