[mlpack-git] master: Add -lm for failing clang build on some systems. http://clang.debian.net/status.php?version=3.5.0&key=UNDEF_REF (6acda7e)

[gitdub at big.cc.gt.atl.ga.us]

Repository : https://github.com/mlpack/mlpack

On branch  : master
Link       : https://github.com/mlpack/mlpack/compare/22bbb89eae5ef8f08b61539865a0beeabe345b34...3ad083bcbf243915de035eead1b0772ac3f35dee

>---------------------------------------------------------------

commit 6acda7e316075a0cb6f1af0b6153de8f8e30c7e5
Author: Ryan Curtin <ryan at ratml.org>
Date:   Mon Jan 12 10:57:25 2015 -0500

    Add -lm for failing clang build on some systems.
    http://clang.debian.net/status.php?version=3.5.0&key=UNDEF_REF


>---------------------------------------------------------------

6acda7e316075a0cb6f1af0b6153de8f8e30c7e5
 CMakeLists.txt | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 31f185d..884d415 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -28,10 +28,12 @@ if(CMAKE_COMPILER_IS_GNUCC OR "${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
 endif(CMAKE_COMPILER_IS_GNUCC OR "${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
 
 # If using clang, we have to link against libstdc++ (at least on some systems).
+# Further, gcc sometimes optimizes calls to math.h functions, making -lm
+# unnecessary with gcc, but it may still be necessary with clang.
 if("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
-  set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -lstdc++")
-  set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} -lstdc++")
-  set(CMAKE_MODULE_LINKER_FLAGS "${CMAKE_MODULE_LINKER_FLAGS} -lstdc++")
+  set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -lstdc++ -lm")
+  set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} -lstdc++ -lm")
+  set(CMAKE_MODULE_LINKER_FLAGS "${CMAKE_MODULE_LINKER_FLAGS} -lstdc++ -lm")
 endif("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
 
 # Debugging CFLAGS.  Turn optimizations off; turn debugging symbols on.