patch 8.0.0914: highlight attributes are always combined
Problem: Highlight attributes are always combined.
Solution: Add the 'nocombine' value to replace attributes instead of
combining them. (scauligi, closes #1963)
diff --git a/src/vim.h b/src/vim.h
index d7d3556..23a000e 100644
--- a/src/vim.h
+++ b/src/vim.h
@@ -680,7 +680,8 @@
#define HL_UNDERLINE 0x08
#define HL_UNDERCURL 0x10
#define HL_STANDOUT 0x20
-#define HL_ALL 0x3f
+#define HL_NOCOMBINE 0x40
+#define HL_ALL 0x7f
/* special attribute addition: Put message in history */
#define MSG_HIST 0x1000