Fix bug#56267:

tcmalloc lib (libtcmalloc_minimal.so) is missing from mysql 5.5 binary

Ensure that a "-DMALLOC_LIB=/foo/bar/libtcmalloc_minimal.so"
will ensure that this library gets included in the tar.gz
binary package.

It depends on the build environment to set this variable
to the correct path name, if it is available.

scripts/CMakeLists.txt

@@ -81,12 +81,11 @@ INSTALL(FILES
 )
 
 # TCMalloc hacks
-IF($ENV{MALLOC_LIB})
-  SET(MALLOC_LIB $ENV{MALLOC_LIB} CACHE STRING "malloc library")
-ENDIF()
-
 IF(MALLOC_LIB)
-  INSTALL(FILES ${MALLOC_LIB} DESTINATION lib OPTIONAL)
+  MESSAGE("Using tcmalloc '${MALLOC_LIB}'")
+  INSTALL(FILES ${MALLOC_LIB} DESTINATION ${INSTALL_LIBDIR} OPTIONAL)
+ELSE()
+  MESSAGE("No 'MALLOC_LIB' variable")
 ENDIF()
 
 IF(CMAKE_GENERATOR MATCHES "Makefiles")