diff -ruN clapack-3.2.1-CMAKE.orig/CMakeLists.txt clapack-3.2.1-CMAKE/CMakeLists.txt
--- clapack-3.2.1-CMAKE.orig/CMakeLists.txt	2011-06-17 23:01:05.275747599 +0200
+++ clapack-3.2.1-CMAKE/CMakeLists.txt	2011-06-17 23:07:49.128747755 +0200
@@ -30,6 +30,28 @@
 
 set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fPIC")
 
+if(BLAS_LIBRARIES)
+  include(CheckFortranFunctionExists)
+  set(CMAKE_REQUIRED_LIBRARIES ${BLAS_LIBRARIES})
+  CHECK_FORTRAN_FUNCTION_EXISTS("dgemm" BLAS_FOUND)
+  unset( CMAKE_REQUIRED_LIBRARIES )
+  if(BLAS_FOUND)
+    message(STATUS "--> BLAS supplied by user is WORKING, will use ${BLAS_LIBRARIES}.")
+  else(BLAS_FOUND)
+    message(ERROR "--> BLAS supplied by user is not WORKING, CANNOT USE ${BLAS_LIBRARIES}.")
+    message(ERROR "-->     Will use REFERENCE BLAS (by default)")
+    message(ERROR "-->     Or Correct your BLAS_LIBRARIES entry ")
+    message(ERROR "-->     Or Consider checking USE_OPTIMIZED_BLAS")
+  endif(BLAS_FOUND)
+else(BLAS_LIBRARIES)
+   # User did not provide a BLAS Library
+   find_package( BLAS )
+endif (BLAS_LIBRARIES)
+
+if(NOT BLAS_FOUND)
+    message(FATAL_ERROR "--> BLAS libraries needed but not found.")
+endif(NOT BLAS_FOUND)
+
 add_subdirectory(SRC)
 
 if(ENABLE_TESTS)
@@ -44,4 +66,3 @@
   ${CLAPACK_BINARY_DIR}/clapack-config-version.cmake @ONLY)
 configure_file(${CLAPACK_SOURCE_DIR}/clapack-config.cmake.in
   ${CLAPACK_BINARY_DIR}/clapack-config.cmake @ONLY)
-
diff -ruN clapack-3.2.1-CMAKE.orig/SRC/CMakeLists.txt clapack-3.2.1-CMAKE/SRC/CMakeLists.txt
--- clapack-3.2.1-CMAKE.orig/SRC/CMakeLists.txt	2011-06-17 23:01:05.276747599 +0200
+++ clapack-3.2.1-CMAKE/SRC/CMakeLists.txt	2011-06-17 23:08:43.761747789 +0200
@@ -377,7 +377,7 @@
 endif()
 
 add_library(clapack SHARED ${ALLOBJ} ${ALLXOBJ})
-target_link_libraries(clapack blas f2c m)
+target_link_libraries(clapack ${BLAS_LIBRARIES} f2c m)
 set_target_properties(clapack PROPERTIES SOVERSION "${CLAPACK_VERSION}")
 
 install(