Fix jonas#856: Add CURSES_CFLAGS to CPPFLAGS (jonas#857)

According to `tools/ax_with_curses.m4` `CURSES_CPPFLAGS` was renamed to
`CURSES_CFLAGS` for compatibility with `pkg-config`, so add the flags to
`CPPFLAGS`.

References Linuxbrew/homebrew-core#8440

NEWS.adoc

@@ -1,6 +1,13 @@
 Release notes
 =============
 
+master
+------
+
+Bug fixes:
+
+ - Add `CURSES_CFLAGS` to `CPPFLAGS`. (#856, Linuxbrew/homebrew-core#8440)
+
 tig-2.4.0
 ---------
 
@@ -36,7 +43,7 @@ Bug fixes:
  - Use fully qualified reference name for tags when conflicting with branch
    name. (#746, #787, #849)
  - Fix resize not working after entering command. (#845) (#846)
- - Use stack allocated memory to handle TIG_LS_REMOTE. (#839)
+ - Use stack allocated memory to handle `TIG_LS_REMOTE`. (#839)
  - Fix deleted file mode line remains highlighted after hovering in diff or stage view. (#851)
  - Fix `TIG_LS_REMOTE` not working with git-ls-remote(1). (#853, #854)
 

config.make.in

@@ -10,7 +10,8 @@ sysconfdir = @sysconfdir@
 
 CC = @CC@
 CFLAGS = @CFLAGS@ @COVERAGE_CFLAGS@
-CPPFLAGS = @CPPFLAGS@ -DHAVE_CONFIG_H
+# CURSES_CFLAGS contain `-I..` flags so add to preprocessor flags.
+CPPFLAGS = @CPPFLAGS@ @CURSES_CFLAGS@ -DHAVE_CONFIG_H
 LDFLAGS = @LDFLAGS@
 LDLIBS = @LIBS@ @CURSES_LIBS@