SpatialaudioConfig: add versioning

With a string value and a value that can be compared between versions.

Author: robUx4

include/SpatialaudioConfig.h.in

@@ -10,6 +10,13 @@
 #ifndef SPATIALAUDIO_CONFIG_H
 #define SPATIALAUDIO_CONFIG_H
 
+#define SPATIALAUDIO_MAJOR @CMAKE_PROJECT_VERSION_MAJOR@
+#define SPATIALAUDIO_MINOR @CMAKE_PROJECT_VERSION_MINOR@
+#define SPATIALAUDIO_PATCH @CMAKE_PROJECT_VERSION_PATCH@
+#define SPATIALAUDIO_VERSION_STR "@CMAKE_PROJECT_VERSION@"
+
+#define SPATIALAUDIO_VERSION ((@CMAKE_PROJECT_VERSION_MAJOR@ << 16) | (@CMAKE_PROJECT_VERSION_MINOR@ << 8) | @CMAKE_PROJECT_VERSION_PATCH@)
+
 // True if libspatialaudio was built with libmysofa support
 #cmakedefine01 SPATIALAUDIO_SUPPORTS_SOFA