diff --git a/libm/Android.mk b/libm/Android.mk
index d7d8bc1..4dfb216 100644
--- a/libm/Android.mk
+++ b/libm/Android.mk
@@ -239,6 +239,7 @@
     -Wno-sign-compare \
     -Wno-uninitialized \
     -Wno-unknown-pragmas \
+    -fvisibility=hidden \
 
 libm_common_includes := $(LOCAL_PATH)/upstream-freebsd/lib/msun/src/
 
diff --git a/libm/include/fenv.h b/libm/include/fenv.h
index 6966e0d..73ecc80 100644
--- a/libm/include/fenv.h
+++ b/libm/include/fenv.h
@@ -34,6 +34,7 @@
 #include <machine/fenv.h>
 
 __BEGIN_DECLS
+#pragma GCC visibility push(default)
 
 int feclearexcept(int);
 int fegetexceptflag(fexcept_t *, int);
@@ -64,6 +65,7 @@
 extern const fenv_t __fe_dfl_env;
 #define FE_DFL_ENV  (&__fe_dfl_env)
 
+#pragma GCC visibility pop
 __END_DECLS
 
 #endif  /* ! _FENV_H_ */
diff --git a/libm/include/math.h b/libm/include/math.h
index c264583..4faec33 100644
--- a/libm/include/math.h
+++ b/libm/include/math.h
@@ -20,6 +20,9 @@
 #include <sys/cdefs.h>
 #include <limits.h>
 
+__BEGIN_DECLS
+#pragma GCC visibility push(default)
+
 /*
  * ANSI/POSIX
  */
@@ -165,7 +168,7 @@
  * effect of raising floating-point exceptions, so they are not declared
  * as __pure2.  In C99, FENV_ACCESS affects the purity of these functions.
  */
-__BEGIN_DECLS
+
 /*
  * ANSI/POSIX
  */
@@ -282,6 +285,7 @@
 double	drem(double, double);
 int	finite(double) __pure2;
 int	isnanf(float) __pure2;
+long double significandl(long double);
 
 /*
  * Reentrant version of gamma & lgamma; passes signgam back by reference
@@ -464,6 +468,7 @@
 void sincosl(long double, long double*, long double*);
 #endif /* _GNU_SOURCE */
 
+#pragma GCC visibility pop
 __END_DECLS
 
 #endif /* !_MATH_H_ */
diff --git a/tests/math_test.cpp b/tests/math_test.cpp
index 63ac719..b0d541a 100644
--- a/tests/math_test.cpp
+++ b/tests/math_test.cpp
@@ -1067,8 +1067,6 @@
   ASSERT_FLOAT_EQ(1.5375f, significandf(12.3f));
 }
 
-extern "C" long double significandl(long double); // BSD's <math.h> doesn't declare this.
-
 TEST(math, significandl) {
   ASSERT_DOUBLE_EQ(0.0L, significandl(0.0L));
   ASSERT_DOUBLE_EQ(1.2L, significandl(1.2L));