diff --git a/src/structs.h b/src/structs.h
index adee3e8..1775256 100644
--- a/src/structs.h
+++ b/src/structs.h
@@ -84,7 +84,9 @@
 # ifdef FEAT_XCLIPBOARD
 #  include <X11/Intrinsic.h>
 # endif
-# define guicolor_T int		/* avoid error in prototypes */
+# define guicolor_T long_u		/* avoid error in prototypes and 
+					 * make FEAT_TERMTRUECOLOR work */
+# define INVALCOLOR ((guicolor_T)0x1ffffff)
 #endif
 
 /*
@@ -911,6 +913,10 @@
 	    /* These colors need to be > 8 bits to hold 256. */
 	    short_u	    fg_color;	/* foreground color number */
 	    short_u	    bg_color;	/* background color number */
+# ifdef FEAT_TERMTRUECOLOR
+	    long_u	    fg_rgb;	/* foreground color RGB */
+	    long_u	    bg_rgb;	/* background color RGB */
+# endif
 	} cterm;
 # ifdef FEAT_GUI
 	struct