maint: prohibit empty first lines

Based on discussion with Eric:

https://www.redhat.com/archives/libvir-list/2014-March/msg01001.html

Signed-off-by: Martin Kletzander <mkletzan@redhat.com>

diff --git a/cfg.mk b/cfg.mk
index b5f1fa20d0ad7f3a0e90117a316e0c64de31e42c..10ad74442f502661ea33322644012ba1920d1593 100644 (file)
--- a/cfg.mk
+++ b/cfg.mk
@@ -936,6 +936,13 @@ sc_require_locale_h:
        halt='setlocale() requires <locale.h>'                          \
          $(_sc_search_regexp)
 
+sc_prohibit_empty_first_line:
+       @awk 'BEGIN { fail=0; }                                         \
+       FNR == 1 { if ($$0 == "") { print FILENAME ":1:"; fail=1; } }   \
+       END { if (fail == 1) {                                          \
+         print "$(ME): Prohibited empty first line" > "/dev/stderr";   \
+       } exit fail; }' $$($(VC_LIST_EXCEPT));
+
 # We don't use this feature of maint.mk.
 prev_version_file = /dev/null
 
@@ -1115,3 +1122,6 @@ exclude_file_name_regexp--sc_avoid_attribute_unused_in_header = \
 
 exclude_file_name_regexp--sc_prohibit_mixed_case_abbreviations = \
   ^src/(vbox/vbox_CAPI.*.h|esx/esx_vi.(c|h)|esx/esx_storage_backend_iscsi.c)$$
+
+exclude_file_name_regexp--sc_prohibit_empty_first_line = \
+  ^(README|daemon/THREADS\.txt|src/esx/README|docs/library.xen|tests/vmwareverdata/fusion-5.0.3.txt)$$