[gimp/meson] Fix macro (def/undef) -> (def 1 / undef)

[Félix Piédallu <fpiedallu src gnome org>]

commit f33c76b17312fd45aa5e151cb7d70b3a1fc8aad6
Author: Félix Piédallu <felix piedallu me>
Date:   Thu Feb 15 15:52:13 2018 +0100

    Fix macro (def/undef) -> (def 1 / undef)

 meson.build |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/meson.build b/meson.build
index 38a7846..dd8e35a 100644
--- a/meson.build
+++ b/meson.build
@@ -992,7 +992,7 @@ foreach fn : [
     'vprintf',
   ]
   macro_name = 'HAVE_' + fn.to_upper().underscorify()
-  conf.set(macro_name, cc.has_function(fn))
+  conf.set(macro_name, cc.has_function(fn) ? 1 : false)
 endforeach
 
 
@@ -1023,7 +1023,7 @@ foreach header : [
     'unistd.h',
   ]
   macro_name = 'HAVE_' + header.to_upper().underscorify()
-  conf.set(macro_name, cc.has_header(header))
+  conf.set(macro_name, cc.has_header(header) ? 1 : false)
 endforeach
 
 conf.set('HAVE_MMAN_H', cc.has_header('sys/mman.h'))