- Do not depend on dhm code if POLARSSL_DHM_C not defined

diff --git a/library/x509parse.c b/library/x509parse.c
index b13fbde..9d0ebd2 100644
--- a/library/x509parse.c
+++ b/library/x509parse.c
@@ -2049,6 +2049,7 @@
     return( ret );
 }
 
+#if defined(POLARSSL_DHM_C)
 /*
  * Parse DHM parameters
  */
@@ -2150,6 +2151,7 @@
 
     return( ret );
 }
+#endif /* POLARSSL_DHM_C */
 
 #if defined _MSC_VER && !defined snprintf
 #include <stdarg.h>