Ignore function pointer cast warnings

Use GCC pragmas as these warnings are enabled by -Wpedantic and there's
no way to disable them selectively.
diff --git a/xmlmodule.c b/xmlmodule.c
index e3a8bd6..a95ab66 100644
--- a/xmlmodule.c
+++ b/xmlmodule.c
@@ -340,6 +340,7 @@
 static int
 xmlModulePlatformSymbol(void *handle, const char *name, void **symbol)
 {
+XML_IGNORE_PEDANTIC_WARNINGS
 #ifdef _WIN32_WCE
     /*
      * GetProcAddressA seems only available on WinCE
@@ -349,6 +350,7 @@
     *symbol = GetProcAddress(handle, name);
 #endif
     return (NULL == *symbol) ? -1 : 0;
+XML_POP_WARNINGS
 }
 
 #endif /* _WIN32 */