diff --git a/newlib/libm/common/fdlibm.h b/newlib/libm/common/fdlibm.h
index 8dffc832d..7a49e29e0 100644
--- a/newlib/libm/common/fdlibm.h
+++ b/newlib/libm/common/fdlibm.h
@@ -160,6 +160,7 @@ extern double __ieee754_fmod __P((double,double));
 extern double __ieee754_pow __P((double,double));
 extern double __ieee754_lgamma_r __P((double,int *));
 extern double __ieee754_gamma_r __P((double,int *));
+extern double __ieee754_tgamma __P((double));
 extern double __ieee754_log10 __P((double));
 extern double __ieee754_sinh __P((double));
 extern double __ieee754_hypot __P((double,double));
@@ -206,6 +207,7 @@ extern float __ieee754_fmodf __P((float,float));
 extern float __ieee754_powf __P((float,float));
 extern float __ieee754_lgammaf_r __P((float,int *));
 extern float __ieee754_gammaf_r __P((float,int *));
+extern float __ieee754_tgammaf __P((float));
 extern float __ieee754_log10f __P((float));
 extern float __ieee754_sinhf __P((float));
 extern float __ieee754_hypotf __P((float,float));