diff --git a/libtcc.c b/libtcc.c
index 432b301..17dd33f 100644
--- a/libtcc.c
+++ b/libtcc.c
@@ -956,6 +956,9 @@ LIBTCCAPI TCCState *tcc_new(void)
     tcc_define_symbol(s, "__builtin_nanf(ignored_string)", "__nan()");
     /* used by _fd_def.h */
     tcc_define_symbol(s, "__builtin_bzero(p, ignored_size)", "bzero(p, sizeof(*(p)))");
+    /* used by floats.h to implement FLT_ROUNDS C99 macro. 1 == to nearest */
+    tcc_define_symbol(s, "__builtin_flt_rounds()", "1");
+
     /* avoids usage of GCC/clang specific builtins in libc-headerfiles: */
     tcc_define_symbol(s, "__FINITE_MATH_ONLY__", "1");
     tcc_define_symbol(s, "_FORTIFY_SOURCE", "0");