Better libTIFF test

config.h.in

@@ -53,6 +53,9 @@
 /* Define to 1 if libPNG is available */
 #undef HAVE_LIBPNG
 
+/* Define to 1 if you have the `tiff' library (-ltiff). */
+#undef HAVE_LIBTIFF
+
 /* Define to 1 if your system has a GNU libc compatible `malloc' function, and
    to 0 otherwise. */
 #undef HAVE_MALLOC

configure

@@ -7002,15 +7002,59 @@ if test "${with_libtiff+set}" = set; then :
   withval=$with_libtiff;
       LIBTIFF_CFLAGS="-I$withval/include"
       LIBTIFF_LIBS="-L$withval/lib -ltiff"
+      have_libtiff=true
 
 else
 
-      LIBTIFF_LIBS="-ltiff"
+      { $as_echo "$as_me:${as_lineno-$LINENO}: checking for TIFFOpen in -ltiff" >&5
+$as_echo_n "checking for TIFFOpen in -ltiff... " >&6; }
+if test "${ac_cv_lib_tiff_TIFFOpen+set}" = set; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_check_lib_save_LIBS=$LIBS
+LIBS="-ltiff  $LIBS"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char TIFFOpen ();
+int
+main ()
+{
+return TIFFOpen ();
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  ac_cv_lib_tiff_TIFFOpen=yes
+else
+  ac_cv_lib_tiff_TIFFOpen=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_tiff_TIFFOpen" >&5
+$as_echo "$ac_cv_lib_tiff_TIFFOpen" >&6; }
+if test "x$ac_cv_lib_tiff_TIFFOpen" = x""yes; then :
+  cat >>confdefs.h <<_ACEOF
+#define HAVE_LIBTIFF 1
+_ACEOF
+
+  LIBS="-ltiff $LIBS"
 
+else
+  have_libtiff=true
 fi
 
 
-$as_echo "#define HAVE_TIFF 1" >>confdefs.h
+fi
 
 
 else
@@ -7018,6 +7062,13 @@ else
    { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
 $as_echo "no" >&6; }
 
+fi
+if test x$have_libtiff = xtrue; then :
+
+
+$as_echo "#define HAVE_TIFF 1" >>confdefs.h
+
+
 fi
 
 

configure.ac

@@ -157,13 +157,17 @@ AS_IF([test "x$enable_tiff" != "xno"],
    [
       LIBTIFF_CFLAGS="-I$withval/include"
       LIBTIFF_LIBS="-L$withval/lib -ltiff"
+      have_libtiff=true
    ], [
-      LIBTIFF_LIBS="-ltiff"
+      AC_CHECK_LIB([tiff], [TIFFOpen], [], [have_libtiff=true])
    ])
-   AC_DEFINE([HAVE_TIFF], [1], [Define to 1 if libTIFF is available])
 ], [
    AC_MSG_RESULT([no])
 ])
+AS_IF([test x$have_libtiff = xtrue],
+[
+   AC_DEFINE([HAVE_TIFF], [1], [Define to 1 if libTIFF is available])
+])
 
 
 AC_MSG_CHECKING([whether to use Cairo])