Add the INSTALLMODE enumeration.

include/msi.h

@@ -136,6 +136,15 @@ typedef enum tagINSTALLLOGATTRIBUTES
     INSTALLLOGATTRIBUTES_FLUSHEACHLINE = 0x00000002
 } INSTALLLOGATTRIBUTES;
 
+typedef enum tagINSTALLMODE
+{
+    INSTALLMODE_NODETECTION_ANY     = -4,
+    INSTALLMODE_NOSOURCERESOLUTION  = -3,
+    INSTALLMODE_NODETECTION         = -2,
+    INSTALLMODE_EXISTING            = -1,
+    INSTALLMODE_DEFAULT             = 0
+} INSTALLMODE;
+
 typedef enum tagADVERTISEFLAGS
 {
     ADVERTISEFLAGS_MACHINEASSIGN = 0,