configure: mac and iOS should compile core/unix/*.c

macOS currently needs this if you build with X11 support. iOS doesn't
(currently), but it doesn't hurt to compile it in case we do something
Unixy on that platform later on.

configure

@@ -24124,6 +24124,8 @@ $as_echo "#define SDL_TIMER_UNIX 1" >>confdefs.h
             SOURCES="$SOURCES $srcdir/src/timer/unix/*.c"
             have_timers=yes
         fi
+        # Set up other core UNIX files
+        SOURCES="$SOURCES $srcdir/src/core/unix/*.c"
         # The iOS platform requires special setup.
 
 $as_echo "#define SDL_VIDEO_DRIVER_UIKIT 1" >>confdefs.h
@@ -24231,6 +24233,8 @@ $as_echo "#define SDL_TIMER_UNIX 1" >>confdefs.h
         if test x$enable_file = xyes; then
             SOURCES="$SOURCES $srcdir/src/file/cocoa/*.m"
         fi
+        # Set up other core UNIX files
+        SOURCES="$SOURCES $srcdir/src/core/unix/*.c"
         # The Mac OS X platform requires special setup.
         EXTRA_CFLAGS="$EXTRA_CFLAGS -fpascal-strings"
         EXTRA_LDFLAGS="$EXTRA_LDFLAGS -lobjc"

configure.in

@@ -3595,6 +3595,8 @@ AC_HELP_STRING([--enable-render-d3d], [enable the Direct3D render driver [[defau
             SOURCES="$SOURCES $srcdir/src/timer/unix/*.c"
             have_timers=yes
         fi
+        # Set up other core UNIX files
+        SOURCES="$SOURCES $srcdir/src/core/unix/*.c"
         # The iOS platform requires special setup.
         AC_DEFINE(SDL_VIDEO_DRIVER_UIKIT, 1, [ ])
         AC_DEFINE(SDL_VIDEO_OPENGL_ES2, 1, [ ])
@@ -3680,6 +3682,8 @@ AC_HELP_STRING([--enable-render-d3d], [enable the Direct3D render driver [[defau
         if test x$enable_file = xyes; then
             SOURCES="$SOURCES $srcdir/src/file/cocoa/*.m"
         fi
+        # Set up other core UNIX files
+        SOURCES="$SOURCES $srcdir/src/core/unix/*.c"
         # The Mac OS X platform requires special setup.
         EXTRA_CFLAGS="$EXTRA_CFLAGS -fpascal-strings"
         EXTRA_LDFLAGS="$EXTRA_LDFLAGS -lobjc"