CMakeLists.txt: Indicate if APNG support is available.

Note that APNG s loaded using dlopen(), so even if it isn't available
at compile-time, it might be available at runtime.

CMakeLists.txt

@@ -249,6 +249,20 @@ ELSE(ENABLE_DECRYPTION)
 	SET(ENABLE_DECRYPTION_MSG "Disabled")
 ENDIF(ENABLE_DECRYPTION)
 
+IF(HAVE_PNG)
+	IF(USE_INTERNAL_PNG)
+		SET(HAVE_PNG_APNG_MSG "Yes (bundled)")
+	ELSE(USE_INTERNAL_PNG)
+		IF(HAVE_PNG_APNG)
+			SET(HAVE_PNG_APNG_MSG "Yes (system)")
+		ELSE(HAVE_PNG_APNG)
+			SET(HAVE_PNG_APNG_MSG "No (system)")
+		ENDIF(HAVE_PNG_APNG)
+	ENDIF(USE_INTERNAL_PNG)
+ELSE(HAVE_PNG)
+	SET(HAVE_PNG_APNG_MSG "No (library not found?)")
+ENDIF(HAVE_PNG)
+
 IF(ENABLE_XML)
 	IF(USE_INTERNAL_XML)
 		SET(ENABLE_XML_MSG "Enabled (bundled)")
@@ -343,6 +357,7 @@ Build Summary:
 - libromdata is built as: ${LIBROMDATA_LIB_TYPE}
 - Security mechanism: ${SECURITY_MECHANISM}
 - Decryption functionality: ${ENABLE_DECRYPTION_MSG}
+- APNG support: ${HAVE_PNG_APNG_MSG}
 - XML parsing: ${ENABLE_XML_MSG}
 - PVRTC decoder: ${ENABLE_PVRTC_MSG}
 - ZSTD decompression: ${ENABLE_ZSTD_MSG}