cmake: Add release candidate versions/cmake variables

Allows specifying a release candidate version, and outputs release
candidate version variables to libobs/obs-config.h.  Useful for using
cmake to specify a release candidate version.

libobs/obs-config.h

@@ -61,6 +61,11 @@
 # define OBS_INSTALL_PREFIX ""
 # define OBS_PLUGIN_DESTINATION "obs-plugins"
 # define OBS_RELATIVE_PREFIX "../../"
+# define OBS_RELEASE_CANDIDATE_MAJOR 0
+# define OBS_RELEASE_CANDIDATE_MINOR 0
+# define OBS_RELEASE_CANDIDATE_PATCH 0
+# define OBS_RELEASE_CANDIDATE_VER 0
+# define OBS_RELEASE_CANDIDATE 0
 #endif
 
 #define OBS_INSTALL_DATA_PATH OBS_INSTALL_PREFIX OBS_DATA_PATH

libobs/obsconfig.h.in

@@ -22,3 +22,20 @@
 #define LIBOBS_IMAGEMAGICK_DIR_STYLE_6L 6
 #define LIBOBS_IMAGEMAGICK_DIR_STYLE_7GE 7
 #define LIBOBS_IMAGEMAGICK_DIR_STYLE @LIBOBS_IMAGEMAGICK_DIR_STYLE@
+
+/* NOTE: Release candidate version numbers internally are always the previous
+ * main release number!  For example, if the current public release is 21.0 and
+ * the build is 22.0 release candidate 1, internally the build number (defined
+ * by LIBOBS_API_VER/etc) will always be 21.0, despite the OBS_VERSION string
+ * saying "22.0 RC1".
+ *
+ * If the release candidate version number is 0.0.0 and the RC number is 0,
+ * that means it's not a release candidate build. */
+#define OBS_RELEASE_CANDIDATE_MAJOR @OBS_RELEASE_CANDIDATE_MAJOR@
+#define OBS_RELEASE_CANDIDATE_MINOR @OBS_RELEASE_CANDIDATE_MINOR@
+#define OBS_RELEASE_CANDIDATE_PATCH @OBS_RELEASE_CANDIDATE_PATCH@
+#define OBS_RELEASE_CANDIDATE_VER \
+	MAKE_SEMANTIC_VERSION(OBS_RELEASE_CANDIDATE_MAJOR, \
+	                      OBS_RELEASE_CANDIDATE_MINOR, \
+	                      OBS_RELEASE_CANDIDATE_PATCH)
+#define OBS_RELEASE_CANDIDATE @OBS_RELEASE_CANDIDATE@