diff --git a/configure b/configure
index fc78d87aebf..bbdf04b67d5 100755
--- a/configure
+++ b/configure
@@ -23023,7 +23023,7 @@ cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
 wine_fn_output_makedep ()
 {
     as_dir=tools; as_fn_mkdir_p
-    $CC -I${wine_srcdir}tools -Iinclude -I${wine_srcdir}include -D__WINESRC__ $EXTRACFLAGS $CPPFLAGS $CFLAGS -o tools/makedep$ac_exeext ${wine_srcdir}tools/makedep.c $LDFLAGS
+    $CC -I${wine_srcdir}tools -Iinclude -I${wine_srcdir}include -D__WINESRC__ -DWINE_UNIX_LIB $EXTRACFLAGS $CPPFLAGS $CFLAGS -o tools/makedep$ac_exeext ${wine_srcdir}tools/makedep.c $LDFLAGS
 }
 wine_fn_output_makefile ()
 {
diff --git a/configure.ac b/configure.ac
index e571c32bcdf..58efc37296c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -3462,7 +3462,7 @@ then
 [wine_fn_output_makedep ()
 {
     AS_MKDIR_P(tools)
-    $CC -I${wine_srcdir}tools -Iinclude -I${wine_srcdir}include -D__WINESRC__ $EXTRACFLAGS $CPPFLAGS $CFLAGS -o tools/makedep$ac_exeext ${wine_srcdir}tools/makedep.c $LDFLAGS
+    $CC -I${wine_srcdir}tools -Iinclude -I${wine_srcdir}include -D__WINESRC__ -DWINE_UNIX_LIB $EXTRACFLAGS $CPPFLAGS $CFLAGS -o tools/makedep$ac_exeext ${wine_srcdir}tools/makedep.c $LDFLAGS
 }])
 fi
 
diff --git a/include/windef.h b/include/windef.h
index 28aa7d6a237..b5f8f3d0b4c 100644
--- a/include/windef.h
+++ b/include/windef.h
@@ -54,11 +54,13 @@ extern "C" {
 # endif
 #endif
 
+#if !defined(_MSC_VER) && !defined(__MINGW32__)
+
 #ifdef WINE_UNIX_LIB
 # define __stdcall
 # define __cdecl
 # define __fastcall
-#elif !defined(_MSC_VER) && !defined(__MINGW32__)
+#else
 # undef __stdcall
 # ifdef __i386__
 #  ifdef __GNUC__
@@ -99,6 +101,8 @@ extern "C" {
 # ifndef __thiscall
 #  define __thiscall __stdcall
 # endif
+#endif  /* WINE_UNIX_LIB */
+
 #endif  /* _MSC_VER || __MINGW32__ */
 
 #ifndef __ms_va_list
diff --git a/tools/makedep.c b/tools/makedep.c
index 00ebfa27e8f..3322e825617 100644
--- a/tools/makedep.c
+++ b/tools/makedep.c
@@ -2351,7 +2351,6 @@ static struct strarray get_source_defines( struct makefile *make, struct incl_fi
     }
     strarray_addall( &ret, make->define_args );
     strarray_addall( &ret, get_expanded_file_local_var( make, obj, "EXTRADEFS" ));
-    if (source->file->flags & FLAG_C_UNIX) strarray_add( &ret, "-DWINE_UNIX_LIB" );
     return ret;
 }
 
@@ -4247,6 +4246,7 @@ static void load_sources( struct makefile *make )
     make->define_args = empty_strarray;
     make->unix_cflags = empty_strarray;
     if (!make->extlib) strarray_add( &make->define_args, "-D__WINESRC__" );
+    strarray_add( &make->unix_cflags, "-DWINE_UNIX_LIB" );
 
     value = get_expanded_make_var_array( make, "EXTRAINCL" );
     for (i = 0; i < value.count; i++)