Also detect missing symbols in libssl and libtcl

doc/UPDATES

@@ -5,7 +5,7 @@ maint
   * Fix help for 'topic' to show optional channel argument
   * Fix cmd_hublevel not properly requiring a hublevel argument
   * Fix build with clang (FreeBSD 10)
-  * Fix startup crash when some libcrypto symbols were missing
+  * Fix startup crash when some shared library symbols were missing
 
 1.4.3
   * Default 'set promisc' to ignore since it's usually a false positive

src/libssl.c

@@ -84,7 +84,10 @@ int load_libssl() {
     return(1);
   }
 
-  load_symbols(libssl_handle);
+  if (load_symbols(libssl_handle)) {
+    fprintf(stderr, STR("Missing symbols for libssl (likely too old)\n"));
+    return(1);
+  }
 
   return 0;
 }

src/libtcl.c

@@ -81,7 +81,10 @@ int load_libtcl() {
     return 1;
   }
 
-  load_symbols(libtcl_handle);
+  if (load_symbols(libtcl_handle)) {
+    fprintf(stderr, STR("Missing symbols for libtcl (likely too old)\n"));
+    return(1);
+  }
 
 #ifdef USE_SCRIPT_TCL
   // create interp