Make implicit function declaration an actual error

diff --git a/configure.ac b/configure.ac
index ae7b9467d1f678ff3065876f79b8f83fdc423683..f34275ac569f900065d39cb6140bcabf286d5db3 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -147,6 +147,7 @@ if test "$bird_cflags_default" = yes ; then
   BIRD_CHECK_GCC_OPTION([bird_cv_c_option_wno_pointer_sign], [-Wno-pointer-sign], [-Wall])
   BIRD_CHECK_GCC_OPTION([bird_cv_c_option_wno_missing_init], [-Wno-missing-field-initializers], [-Wall -Wextra])
   BIRD_CHECK_GCC_OPTION([bird_cv_c_option_watomic_implicit_seq_cst], [-Watomic-implicit-seq-cst], [-Wall -Wextra])
+  BIRD_CHECK_GCC_OPTION([bird_cv_c_option_werror_implicit_function_declaration], [-Werror=implicit-function-declaration], [-Wall -Wextra])
 
   if test "$enable_debug" = no; then
     BIRD_CHECK_LTO
@@ -163,6 +164,7 @@ if test "$bird_cflags_default" = yes ; then
   BIRD_ADD_GCC_OPTION([bird_cv_c_option_wno_pointer_sign], [-Wno-pointer-sign])
   BIRD_ADD_GCC_OPTION([bird_cv_c_option_wno_missing_init], [-Wno-missing-field-initializers])
   BIRD_ADD_GCC_OPTION([bird_cv_c_option_watomic_implicit_seq_cst], [-Watomic-implicit-seq-cst])
+  BIRD_ADD_GCC_OPTION([bird_cv_c_option_werror_implicit_function_declaration], [-Werror=implicit-function-declaration])
 fi