add GSL library as an optional dependency

diff --git a/cmake/configure/configure_gsl.cmake b/cmake/configure/configure_gsl.cmake
new file mode 100644 (file)
index 0000000..53568bd
--- /dev/null
+++ b/cmake/configure/configure_gsl.cmake
@@ -0,0 +1,20 @@
+## ---------------------------------------------------------------------
+##
+## Copyright (C) 2012 - 2015 by the deal.II authors
+##
+## This file is part of the deal.II library.
+##
+## The deal.II library is free software; you can use it, redistribute
+## it, and/or modify it under the terms of the GNU Lesser General
+## Public License as published by the Free Software Foundation; either
+## version 2.1 of the License, or (at your option) any later version.
+## The full text of the license can be found in the file LICENSE at
+## the top level of the deal.II distribution.
+##
+## ---------------------------------------------------------------------
+
+#
+# Configuration for the GSL library:
+#
+
+CONFIGURE_FEATURE(GSL)

diff --git a/cmake/modules/FindGSL.cmake b/cmake/modules/FindGSL.cmake
new file mode 100644 (file)
index 0000000..d34649b
--- /dev/null
+++ b/cmake/modules/FindGSL.cmake
@@ -0,0 +1,39 @@
+## ---------------------------------------------------------------------
+##
+## Copyright (C) 2012 - 2015 by the deal.II authors
+##
+## This file is part of the deal.II library.
+##
+## The deal.II library is free software; you can use it, redistribute
+## it, and/or modify it under the terms of the GNU Lesser General
+## Public License as published by the Free Software Foundation; either
+## version 2.1 of the License, or (at your option) any later version.
+## The full text of the license can be found in the file LICENSE at
+## the top level of the deal.II distribution.
+##
+## ---------------------------------------------------------------------
+
+#
+# Try to find the GSL library
+#
+# This module exports
+#
+#   GSL_LIBRARIES
+#   GSL_LINKER_FLAGS
+#
+
+SET(GSL_DIR "" CACHE PATH "An optional hint to an GSL installation")
+SET_IF_EMPTY(GSL_DIR "$ENV{GSL_DIR}")
+
+DEAL_II_FIND_LIBRARY(GSL_LIBRARY
+  NAMES gsl
+  HINTS ${GSL_DIR}
+  PATH_SUFFIXES lib${LIB_SUFFIX} lib64 lib
+  )
+
+
+DEAL_II_PACKAGE_HANDLE(GSL
+  LIBRARIES
+    REQUIRED GSL_LIBRARY
+  CLEAR GSL_LIBRARY
+  )