common/37 has header: Add a test for prefixes

test cases/common/37 has header/meson.build

@@ -1,10 +1,28 @@
 project('has header', 'c', 'cpp')
 
 foreach comp : [meson.get_compiler('c'), meson.get_compiler('cpp')]
-  if comp.has_header('stdio.h') == false
+  if not comp.has_header('stdio.h')
     error('Stdio missing.')
   endif
 
+  # stdio.h doesn't actually need stdlib.h, but I don't know any headers on
+  # UNIX/Linux that need other headers defined beforehand
+  if not comp.has_header('stdio.h', prefix : '#include <stdlib.h>')
+    error('Stdio missing.')
+  endif
+
+  # XInput.h needs windows.h included beforehand. We only do this check on MSVC
+  # because MinGW often defines its own wrappers that pre-include windows.h
+  if comp.get_id() == 'msvc'
+    if not comp.has_header('XInput.h', prefix : '#include <windows.h>')
+      error('XInput.h is missing on Windows')
+    endif
+    if comp.has_header('XInput.h')
+      error('XInput.h needs windows.h')
+    endif
+  endif
+
+
   if comp.has_header('ouagadougou.h')
     error('Found non-existant header.')
   endif