diff --git a/configure.ac b/configure.ac
index 3169c434..ffcdd49f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -439,11 +439,9 @@ AC_ARG_ENABLE(pax_emutramp,
       [Define this if you want to enable pax emulated trampolines])
   fi)
 
-if test x$TARGET = xX86_WIN64; then
-    LT_SYS_SYMBOL_USCORE
-    if test "x$sys_symbol_underscore" = xyes; then
-        AC_DEFINE(SYMBOL_UNDERSCORE, 1, [Define if symbols are underscored.])
-    fi
+LT_SYS_SYMBOL_USCORE
+if test "x$sys_symbol_underscore" = xyes; then
+    AC_DEFINE(SYMBOL_UNDERSCORE, 1, [Define if symbols are underscored.])
 fi
 
 FFI_EXEC_TRAMPOLINE_TABLE=0
diff --git a/src/x86/win32.S b/src/x86/win32.S
index 826a5a0f..d71c8b86 100644
--- a/src/x86/win32.S
+++ b/src/x86/win32.S
@@ -473,7 +473,7 @@ END
 
 #else
 
-#if defined(X86_WIN32)
+#if defined(SYMBOL_UNDERSCORE)
 #define USCORE_SYMBOL(x) _##x
 #else
 #define USCORE_SYMBOL(x) x