Fix issues on Linux and OSX with libraries being located incorrectly

dtool/src/dtoolutil/executionEnvironment.cxx

@@ -486,7 +486,9 @@ read_args() {
     maps.getline(buffer, PATH_MAX);
     char *tail = strrchr(buffer,'/');
     char *head = strchr(buffer,'/');
-    if (tail && head && (strcmp(tail,"/libp3dtool.so")==0)) {
+    if (tail && head && (strcmp(tail,"/libp3dtool.so." PANDA_VERSION_STR)==0)) {
+      _dtool_name = head;
+    } else if (tail && head && (strcmp(tail,"/libp3dtool.so")==0)) {
       _dtool_name = head;
     }
   }
@@ -500,7 +502,9 @@ read_args() {
     for (uint32_t i = 0; i < ic; ++i) {
       const char *buffer = _dyld_get_image_name(i);
       const char *tail = strrchr(buffer, '/');
-      if (tail && (strcmp(tail,"/libp3dtool.dylib")==0)) {
+      if (tail && (strcmp(tail,"/libp3dtool." PANDA_VERSION_STR ".dylib")==0)) {
+        _dtool_name = buffer;
+      } else if (tail && (strcmp(tail,"/libp3dtool.dylib")==0)) {
         _dtool_name = buffer;
       }
     }