more reliable linking with bzip2,

$LIBBZ2_PREFIX is not always set.

git-svn: trunk@4196

configure

@@ -15833,16 +15833,9 @@ echo "${ECHO_T}$ac_cv_libbz2_libs" >&6; }
 
 
 
-    save_LDFLAGS="$LDFLAGS"
-    LDFLAGS="$LIBS -L$LIBBZ2_PREFIX/lib";
-    { echo "$as_me:$LINENO: checking for bzReadOpen in -lbz2" >&5
-echo $ECHO_N "checking for bzReadOpen in -lbz2... $ECHO_C" >&6; }
-if test "${ac_cv_lib_bz2_bzReadOpen+set}" = set; then
-  echo $ECHO_N "(cached) $ECHO_C" >&6
-else
-  ac_check_lib_save_LIBS=$LIBS
-LIBS="-lbz2  $LIBS"
-cat >conftest.$ac_ext <<_ACEOF
+    save_LIBS="$LIBS"
+    LIBS="$LIBBZ2";
+    cat >conftest.$ac_ext <<_ACEOF
 /* confdefs.h.  */
 _ACEOF
 cat confdefs.h >>conftest.$ac_ext
@@ -15882,30 +15875,22 @@ eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
 	 test ! -s conftest.err
        } && test -s conftest$ac_exeext &&
        $as_test_x conftest$ac_exeext; then
-  ac_cv_lib_bz2_bzReadOpen=yes
-else
-  echo "$as_me: failed program was:" >&5
-sed 's/^/| /' conftest.$ac_ext >&5
-
-	ac_cv_lib_bz2_bzReadOpen=no
-fi
-
-rm -f core conftest.err conftest.$ac_objext conftest_ipa8_conftest.oo \
-      conftest$ac_exeext conftest.$ac_ext
-LIBS=$ac_check_lib_save_LIBS
-fi
-{ echo "$as_me:$LINENO: result: $ac_cv_lib_bz2_bzReadOpen" >&5
-echo "${ECHO_T}$ac_cv_lib_bz2_bzReadOpen" >&6; }
-if test $ac_cv_lib_bz2_bzReadOpen = yes; then
 
 cat >>confdefs.h <<\_ACEOF
 #define NOBZ2PREFIX 1
 _ACEOF
 
 
+else
+  echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+
 fi
 
-    LDFLAGS="$save_LDFLAGS"
+rm -f core conftest.err conftest.$ac_objext conftest_ipa8_conftest.oo \
+      conftest$ac_exeext conftest.$ac_ext
+    LIBS="$save_LIBS"
     if test "$HAVE_LIBBZ2" = "yes"; then
 	if test "${ac_cv_header_bzlib_h+set}" = set; then
   { echo "$as_me:$LINENO: checking for bzlib.h" >&5

configure.in

@@ -431,12 +431,12 @@ want_bzip2=$enableval, want_bzip2="yes")
 if test "$want_bzip2" = "yes"
 then
     AC_LIB_LINKFLAGS([bz2])
-    save_LDFLAGS="$LDFLAGS"
-    LDFLAGS="$LIBS -L$LIBBZ2_PREFIX/lib";
-    AC_CHECK_LIB([bz2], [bzReadOpen],
+    save_LIBS="$LIBS"
+    LIBS="$LIBS $LIBBZ2";
+    AC_LINK_IFELSE([AC_LANG_CALL([],[bzReadOpen])],
 		 [AC_DEFINE([NOBZ2PREFIX],1,[bzip funtions do not have bz2 prefix])]
 		)
-    LDFLAGS="$save_LDFLAGS"
+    LIBS="$save_LIBS"
     if test "$HAVE_LIBBZ2" = "yes"; then
 	AC_CHECK_HEADER([bzlib.h],
 			[AC_C_CVE_2008_1372],