patch 8.0.1791: using uint8_t does not work everywhere

Problem:    Using uint8_t does not work everywhere.
Solution:   Use char_u instead.
diff --git a/src/proto/term.pro b/src/proto/term.pro
index 333df92..7eafdef 100644
--- a/src/proto/term.pro
+++ b/src/proto/term.pro
@@ -76,5 +76,5 @@
 void swap_tcap(void);
 guicolor_T gui_get_color_cmn(char_u *name);
 guicolor_T gui_get_rgb_color_cmn(int r, int g, int b);
-void cterm_color2rgb(int nr, uint8_t *r, uint8_t *g, uint8_t *b, uint8_t *ansi_idx);
+void cterm_color2rgb(int nr, char_u *r, char_u *g, char_u *b, char_u *ansi_idx);
 /* vim: set ft=c : */