Add basic support for cmake on linux

cmake/FindMPG123.cmake

@@ -0,0 +1,28 @@
+# - Find mpg123
+# Find the native mpg123 includes and library
+#
+#  MPG123_INCLUDE_DIR - where to find mpg123.h
+#  MPG123_LIBRARIES   - List of libraries when using mpg123.
+#  MPG123_FOUND       - True if mpg123 found.
+
+IF(MPG123_INCLUDE_DIR AND MPG123_LIBRARIES)
+  # Already in cache, be silent
+  SET(MPG123_FIND_QUIETLY TRUE)
+ENDIF(MPG123_INCLUDE_DIR AND MPG123_LIBRARIES)
+
+FIND_PATH(MPG123_INCLUDE_DIR mpg123.h
+          PATHS "${MPG123_DIR}"
+          PATH_SUFFIXES include
+          )
+
+FIND_LIBRARY(MPG123_LIBRARIES NAMES mpg123 mpg123-0
+             PATHS "${MPG123_DIR}"
+             PATH_SUFFIXES lib
+             )
+
+# MARK_AS_ADVANCED(MPG123_LIBRARIES MPG123_INCLUDE_DIR)
+
+# handle the QUIETLY and REQUIRED arguments and set MPG123_FOUND to TRUE if
+# all listed variables are TRUE
+INCLUDE(FindPackageHandleStandardArgs)
+FIND_PACKAGE_HANDLE_STANDARD_ARGS(MPG123 DEFAULT_MSG MPG123_LIBRARIES MPG123_INCLUDE_DIR)