Fix for bug 5184. Force checks for GLib, GTK, and libIDL to prevent cached values from interfering if these have been upgraded since the last time configure ran.

build/autoconf/glib.m4

@@ -41,6 +41,9 @@ AC_ARG_ENABLE(glibtest, [  --disable-glibtest       Do not try to compile and ru
       esac
   done
 
+  dnl Force a version check to keep upgraded versions from being overridden by the cached value.
+  unset ac_cv_path_GLIB_CONFIG
+
   AC_PATH_PROG(GLIB_CONFIG, glib-config, no)
   min_glib_version=ifelse([$1], ,0.99.7,$1)
   AC_MSG_CHECKING(for GLIB - version >= $min_glib_version)

build/autoconf/gtk.m4

@@ -29,6 +29,9 @@ AC_ARG_ENABLE(gtktest, [  --disable-gtktest       Do not try to compile and run
      fi
   fi
 
+  dnl Force a version check to keep upgraded versions from being overridden by the cached value.
+  unset ac_cv_path_GTK_CONFIG
+
   AC_PATH_PROG(GTK_CONFIG, gtk-config, no)
   min_gtk_version=ifelse([$1], ,0.99.7,$1)
   AC_MSG_CHECKING(for GTK - version >= $min_gtk_version)

build/autoconf/libIDL.m4

@@ -29,6 +29,9 @@ AC_ARG_ENABLE(libIDLtest, [  --disable-libIDLtest       Do not try to compile an
 
   AM_PATH_GLIB(1.2.0)
 
+  dnl Force a version check to keep upgraded versions from being overridden by the cached value.
+  unset ac_cv_path_LIBIDL_CONFIG
+
   AC_PATH_PROG(LIBIDL_CONFIG, libIDL-config, no)
   min_libIDL_version=ifelse([$1], ,0.6.0,$1)
   AC_MSG_CHECKING(for libIDL - version >= $min_libIDL_version)