diff --git a/ext/iconv/config.m4 b/ext/iconv/config.m4
index 5e2b47245dc..37f82eb4796 100644
--- a/ext/iconv/config.m4
+++ b/ext/iconv/config.m4
@@ -14,7 +14,8 @@ if test "$PHP_ICONV" != "no"; then
   ])
 
   if test "$iconv_avail" != "no"; then
-
+    iconv_cflags_save="$CFLAGS"
+    CFLAGS="$CFLAGS $INCLUDES"
     AC_MSG_CHECKING([if iconv supports errno])
     AC_TRY_RUN([
 #define LIBICONV_PLUG
@@ -107,6 +108,8 @@ int main() {
         ;;
     esac
 
+    CFLAGS="$iconv_cflags_save"
+
     PHP_NEW_EXTENSION(iconv, iconv.c, $ext_shared)
     PHP_SUBST(ICONV_SHARED_LIBADD)
   else