diff --git a/simde/hedley.h b/simde/hedley.h
index 41ac30221..f064f3f4c 100644
--- a/simde/hedley.h
+++ b/simde/hedley.h
@@ -184,6 +184,7 @@
 #  undef HEDLEY_EMSCRIPTEN_VERSION
 #endif
 #if defined(__EMSCRIPTEN__)
+#  include <emscripten.h>
 #  define HEDLEY_EMSCRIPTEN_VERSION HEDLEY_VERSION_ENCODE(__EMSCRIPTEN_major__, __EMSCRIPTEN_minor__, __EMSCRIPTEN_tiny__)
 #endif
 
diff --git a/simde/simde-math.h b/simde/simde-math.h
index 02de568dc..d18bf4f90 100644
--- a/simde/simde-math.h
+++ b/simde/simde-math.h
@@ -1266,7 +1266,7 @@ simde_math_fpclass(double v, const int imm8) {
 
 #if !defined(simde_math_roundeven)
   #if \
-     (!defined(HEDLEY_EMSCRIPTEN_VERSION) && HEDLEY_HAS_BUILTIN(__builtin_roundeven)) || \
+     ((!defined(HEDLEY_EMSCRIPTEN_VERSION) || HEDLEY_EMSCRIPTEN_VERSION_CHECK(3, 1, 43)) && HEDLEY_HAS_BUILTIN(__builtin_roundeven)) || \
       HEDLEY_GCC_VERSION_CHECK(10,0,0)
     #define simde_math_roundeven(v) __builtin_roundeven(v)
   #elif defined(simde_math_round) && defined(simde_math_fabs)
@@ -1286,7 +1286,7 @@ simde_math_fpclass(double v, const int imm8) {
 
 #if !defined(simde_math_roundevenf)
   #if \
-     (!defined(HEDLEY_EMSCRIPTEN_VERSION) && HEDLEY_HAS_BUILTIN(__builtin_roundevenf)) || \
+     ((!defined(HEDLEY_EMSCRIPTEN_VERSION) || HEDLEY_EMSCRIPTEN_VERSION_CHECK(3, 1, 43)) && HEDLEY_HAS_BUILTIN(__builtin_roundevenf)) || \
       HEDLEY_GCC_VERSION_CHECK(10,0,0)
     #define simde_math_roundevenf(v) __builtin_roundevenf(v)
   #elif defined(simde_math_roundf) && defined(simde_math_fabsf)