-fixed some meson issues on windows (becs and tests compilation works. Demos not yet)

-now tests compile proper files
-added setjmp bindings for Windows. It doesn't work on LDC build (singal API could works)

meson.build

@@ -3,10 +3,12 @@ project('decs', 'd', version : '0.5.0')
 # Options
 betterC_opt = get_option('betterC')
 BuildDemos_opt = get_option('BuildDemos')
+BuildTests_opt = get_option('BuildTests')
 LTO_otp = get_option('LTO')
 
 summary('betterC enabled', betterC_opt)
 summary('build demos', BuildDemos_opt)
+summary('build tests', BuildTests_opt)
 summary('LTO enabled', LTO_otp)
 
 meson_minimum_version = '>=0.57.1'
@@ -65,7 +67,9 @@ decs_dep = declare_dependency(
 )
 
 # Tests
-subdir('tests')
+if BuildTests_opt
+	subdir('tests')
+endif
 
 # Demos
 if BuildDemos_opt