syntax-check: Don't include duplicate header

gnulib is excluded.

diff --git a/cfg.mk b/cfg.mk
index e60c4e31c1f87159b7d247bea360ff4267db7895..dd67816e40cf7eb641d1284352a4ef7b70acf7f5 100644 (file)
--- a/cfg.mk
+++ b/cfg.mk
@@ -722,6 +722,30 @@ sc_prohibit_exit_in_tests:
        halt='use return, not exit(), in tests'                         \
          $(_sc_search_regexp)
 
+# Don't include duplicate header in the source (either *.c or *.h)
+sc_prohibit_duplicate_header:
+       @fail=0; for i in $$($(VC_LIST_EXCEPT) | grep '\.[chx]$$'); do  \
+         awk '/# *include.*\.h/ {                                      \
+           match($$0, /[<"][^>"]*[">]/);                               \
+           arr[substr($$0, RSTART + 1, RLENGTH - 2)]++;                \
+         }                                                             \
+         END {                                                         \
+           for (key in arr) {                                          \
+             if (arr[key] > 1) {                                       \
+               fail=1;                                                 \
+               printf("%d %s are included\n", arr[key], key);          \
+             }                                                         \
+           }                                                           \
+           if (fail == 1) {                                            \
+             printf("duplicate header(s) in " FILENAME "\n");          \
+             exit 1;                                                   \
+           }                                                           \
+         }' $$i || fail=1;                                             \
+       done;                                                           \
+       if test $$fail -eq 1; then                                      \
+         { echo "$(ME)": avoid duplicate headers >&2; exit 1; }        \
+       fi;
+
 # We don't use this feature of maint.mk.
 prev_version_file = /dev/null