diff --git a/configure.ac b/configure.ac
index 1b607e0b..ff37794f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -582,6 +582,8 @@ if test "$GCC" = yes; then
           CFLAGS="$CFLAGS -Wno-missing-field-initializers"
           CFLAGS="$CFLAGS -Wno-sign-compare"
           CFLAGS="$CFLAGS -Wno-format-zero-length"
+          CFLAGS="$CFLAGS -Wno-format-truncation"
+          CFLAGS="$CFLAGS -Wno-sizeof-pointer-div"
         fi
         CXXFLAGS="$CXXFLAGS -Wall -Wextra -Wno-shadow"
 
diff --git a/src/b64dec.c b/src/b64dec.c
index 1b845ee4..66ab2ec7 100644
--- a/src/b64dec.c
+++ b/src/b64dec.c
@@ -118,6 +118,7 @@ _gpgme_b64dec_proc (struct b64state *state, void *buffer, size_t length,
           break;
         case s_init:
           ds = s_lfseen;
+          /*FALLTHRU*/
         case s_lfseen:
           if (*s != "-----BEGIN "[pos])
             {
diff --git a/src/cJSON.c b/src/cJSON.c
index 9e53012e..64a54c72 100644
--- a/src/cJSON.c
+++ b/src/cJSON.c
@@ -352,12 +352,15 @@ parse_string (cJSON * item, const char *str, const char **ep)
 		case 4:
 		  *--ptr2 = ((uc | 0x80) & 0xBF);
 		  uc >>= 6;
+                  /*FALLTHRU*/
 		case 3:
 		  *--ptr2 = ((uc | 0x80) & 0xBF);
 		  uc >>= 6;
+                  /*FALLTHRU*/
 		case 2:
 		  *--ptr2 = ((uc | 0x80) & 0xBF);
 		  uc >>= 6;
+                  /*FALLTHRU*/
 		case 1:
 		  *--ptr2 = (uc | firstByteMark[len]);
 		}
diff --git a/src/gpgme-json.c b/src/gpgme-json.c
index a7e3d5f2..e4ae81d0 100644
--- a/src/gpgme-json.c
+++ b/src/gpgme-json.c
@@ -3861,7 +3861,7 @@ main (int argc, char *argv[])
         {
         case CMD_INTERACTIVE:
           opt_interactive = 1;
-          /* Fall trough.  */
+          /*FALLTHROUGH*/
         case CMD_SINGLE:
         case CMD_LIBVERSION:
           cmd = pargs.r_opt;