Add minimalistic HMAC_DRBG implementation

(copied from ECDSA)
diff --git a/visualc/VS6/polarssl.dsp b/visualc/VS6/polarssl.dsp
index 645b29c..f763caa 100644
--- a/visualc/VS6/polarssl.dsp
+++ b/visualc/VS6/polarssl.dsp
@@ -185,6 +185,10 @@
 # End Source File

 # Begin Source File

 

+SOURCE=..\..\library\hmac_drbg.c
+# End Source File
+# Begin Source File
+
 SOURCE=..\..\library\md2.c

 # End Source File

 # Begin Source File

@@ -457,6 +461,10 @@
 # End Source File

 # Begin Source File

 

+SOURCE=..\..\include\polarssl\hmac_drbg.h
+# End Source File
+# Begin Source File
+
 SOURCE=..\..\include\polarssl\md2.h

 # End Source File

 # Begin Source File