[packagechooser] Use the found-directory for AppStream headers

src/modules/packagechooser/Config.cpp

@@ -16,7 +16,6 @@
 
 #ifdef HAVE_APPSTREAM_VERSION
 #include "ItemAppStream.h"
-#include <AppStreamQt/pool.h>
 #include <memory>
 #endif
 

src/modules/packagechooser/ItemAppStream.cpp

@@ -7,20 +7,16 @@
  *
  */
 
-/** @brief Loading items from AppData XML files.
+/** @brief Loading items from AppStream database.
  *
- * Only used if QtXML is found, implements PackageItem::fromAppData().
+ * Only used if AppStreamQt is found, implements PackageItem::fromAppStream().
  */
-#include "PackageModel.h"
+#include "ItemAppStream.h"
 
 #include "locale/TranslationsModel.h"
 #include "utils/Logger.h"
 #include "utils/Variant.h"
 
-#include <AppStreamQt/image.h>
-#include <AppStreamQt/pool.h>
-#include <AppStreamQt/screenshot.h>
-
 /// @brief Return number of pixels in a size, for < ordering purposes
 static inline quint64
 sizeOrder( const QSize& size )

src/modules/packagechooser/ItemAppStream.h

@@ -12,10 +12,28 @@
 
 #include "PackageModel.h"
 
-namespace AppStream
-{
-class Pool;
-}  // namespace AppStream
+/*
+ * This weird include mechanism is because an #include line is allowed
+ * to consist of preprocessor-tokens, which are expanded, and then
+ * the #include is *re*processed. But if it starts with < or ", then
+ * preprocessor tokens are not expanded. So we build up a #include <>
+ * style line with a suitable path -- if we are given a value for
+ * HAVE_APPSTREAM_HEADERS, that is the directory that the AppStreamQt
+ * headers live in.
+ */
+#define CALAMARES_LT <
+#define CALAMARES_GT >
+
+#ifndef HAVE_APPSTREAM_HEADERS
+#define HAVE_APPSTREAM_HEADERS AppStreamQt
+#endif
+
+#include CALAMARES_LT HAVE_APPSTREAM_HEADERS/pool.h CALAMARES_GT
+#include CALAMARES_LT HAVE_APPSTREAM_HEADERS/image.h CALAMARES_GT
+#include CALAMARES_LT HAVE_APPSTREAM_HEADERS/screenshot.h CALAMARES_GT
+
+#undef CALAMARES_LT
+#undef CALAMARES_GT
 
 /** @brief Loads an item from AppStream data.
  *