diff --git a/auto_tests/BUILD b/auto_tests/BUILD
index d94442a1..268532e1 100644
--- a/auto_tests/BUILD
+++ b/auto_tests/BUILD
@@ -12,6 +12,7 @@ cc_library(
     size = "small",
     srcs = [src],
     copts = [
+        "-std=c99",
         "-Wno-parentheses",
     ],
     deps = [
diff --git a/auto_tests/file_saving_test.c b/auto_tests/file_saving_test.c
index 0d167b5a..582013aa 100644
--- a/auto_tests/file_saving_test.c
+++ b/auto_tests/file_saving_test.c
@@ -42,7 +42,7 @@ static void save_data_encrypted(void)
 
     FILE *f = fopen(savefile, "w");
 
-    off_t size = tox_get_savedata_size(t);
+    size_t size = tox_get_savedata_size(t);
     uint8_t *clear = (uint8_t *)malloc(size);
 
     /*this function does not write any data at all*/
diff --git a/toxav/BUILD b/toxav/BUILD
index ab074841..81178f99 100644
--- a/toxav/BUILD
+++ b/toxav/BUILD
@@ -28,6 +28,9 @@ cc_library(
         "toxav.h",
         "video.h",
     ],
+    copts = [
+        "-std=c99",
+    ],
     visibility = ["//visibility:public"],
     deps = [
         "//c-toxcore/toxcore",
diff --git a/toxcore/BUILD b/toxcore/BUILD
index 48ac56fe..8dfa60a5 100644
--- a/toxcore/BUILD
+++ b/toxcore/BUILD
@@ -21,7 +21,7 @@ cc_library(
     hdrs = [
         "crypto_core.h",
     ],
-    visibility = ["//visibility:public"],
+    visibility = ["//c-toxcore:__subpackages__"],
     deps = [
         ":ccompat",
         "@libsodium",
@@ -74,6 +74,7 @@ cc_library(
         "util.h",
     ],
     copts = [
+        "-std=c99",
         "-Wno-parentheses",
     ],
     linkopts = ["-lpthread"],
diff --git a/toxencryptsave/BUILD b/toxencryptsave/BUILD
index 8b49d554..6dfb67b1 100644
--- a/toxencryptsave/BUILD
+++ b/toxencryptsave/BUILD
@@ -13,6 +13,9 @@ cc_library(
         "defines.h",
         "toxencryptsave.h",
     ],
+    copts = [
+        "-std=c99",
+    ],
     visibility = [
         "//visibility:public",
     ],