Use free instead of Free as free checks for NULL.

src/libespeak-ng/dictionary.c

 	size = GetFileLength(fname);
 
 	if (tr->data_dictlist != NULL) {
-		Free(tr->data_dictlist);
+		free(tr->data_dictlist);
 		tr->data_dictlist = NULL;
 	}
 

src/libespeak-ng/speech.c

 	return p;
 }
 
-void Free(void *ptr)
-{
-	if (ptr != NULL)
-		free(ptr);
-}
-
 #pragma GCC visibility push(default)
 
 ESPEAK_NG_API void espeak_ng_InitializePath(const char *path)
 		out_samplerate = 0;
 	}
 #endif
-	Free(event_list);
+	free(event_list);
 	event_list = NULL;
-	Free(outbuf);
+	free(outbuf);
 	outbuf = NULL;
 	FreePhData();
 	FreeVoiceList();

src/libespeak-ng/speech.h

 extern ESPEAK_NG_API void strncpy0(char *to, const char *from, int size);
 extern ESPEAK_NG_API int  GetFileLength(const char *filename);
 char *Alloc(int size);
-void Free(void *ptr);
 
 #ifdef __cplusplus
 }

src/libespeak-ng/synthdata.c

 		return create_file_error_context(context, errno, buf);
 
 	if (*ptr != NULL)
-		Free(*ptr);
+		free(*ptr);
 
 	if ((*ptr = Alloc(length)) == NULL) {
 		fclose(f_in);
 	if (fread(*ptr, 1, length, f_in) != length) {
 		int error = errno;
 		fclose(f_in);
-		Free(*ptr);
+		free(*ptr);
 		return create_file_error_context(context, error, buf);
 	}
 
 
 void FreePhData(void)
 {
-	Free(phoneme_tab_data);
-	Free(phoneme_index);
-	Free(phondata_ptr);
-	Free(tunes);
+	free(phoneme_tab_data);
+	free(phoneme_index);
+	free(phondata_ptr);
+	free(tunes);
 	phoneme_tab_data = NULL;
 	phoneme_index = NULL;
 	phondata_ptr = NULL;

src/libespeak-ng/translate.c

 void DeleteTranslator(Translator *tr)
 {
 	if (tr->data_dictlist != NULL)
-		Free(tr->data_dictlist);
-	Free(tr);
+		free(tr->data_dictlist);
+	free(tr);
 }
 
 int lookupwchar(const unsigned short *list, int c)