- Some compatibility hack with newer libtool versions

- aclocal.m4: ACX_PTHREAD, also check for user set ldflag

ChangeLog

@@ -1,5 +1,6 @@
 0.8.2
 =====
+  07-Apr-2012:  - Some compatibility hack with newer libtool versions
   10-Jul-2011:  - Added --with-included-libtool to configure to allow
                   forcing the use of the included libltdl
 

acinclude.m4

@@ -58,7 +58,7 @@ acx_pthread_ok=no
 # First of all, check if the user has set any of the PTHREAD_LIBS,
 # etcetera environment variables, and if threads linking works using
 # them:
-if test x"$PTHREAD_LIBS$PTHREAD_CFLAGS" != x; then
+if test x"$PTHREAD_LIBS$PTHREAD_CFLAGS$PTHREAD_LDFLAGS" != x; then
         save_CFLAGS="$CFLAGS"
         CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
         save_LDFLAGS="$LDFLAGS"

src/plugins.h

@@ -29,6 +29,12 @@
 #endif
 
 
+///* libtool 2.2 / 2.4 */
+#ifndef lt__PROGRAM__LTX_preloaded_symbols
+#define lt__PROGRAM__LTX_preloaded_symbols lt_libltdl_LTX_preloaded_symbols
+//extern const void *lt_preloaded_symbols[];
+#endif
+
 /* Plugins must return STS_SUCCESS / SUCCESS_FAILURE */