gnu: trilinos-for-dealii-openmpi: Fix build.

This fixes the error

  error: ‘std::hypot’ has not been declared

caused by using an older version of gcc, but requires some patches to
placate newer versions of gcc.

* gnu/packages/maths.scm (trilinos-for-dealii-openmpi)[origin]: Add
patches.
[native-inputs]: Remove gcc-7.
* gnu/packages/patches/teuchos-remove-duplicate-using.patch: New file.
* gnu/packages/patches/tpetra-remove-duplicate-using.patch: Likewise.
* gnu/local.mk (dist_patch_DATA): Register them.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>

1 files changed, 34 insertions, 0 deletions

diff --git a/gnu/packages/patches/teuchos-remove-duplicate-using.patch b/gnu/packages/patches/teuchos-remove-duplicate-using.patch
new file mode 100644
index 0000000000..55cd3f6fc3
--- /dev/null
+++ b/gnu/packages/patches/teuchos-remove-duplicate-using.patch
@@ -0,0 +1,34 @@
+commit e27d9ae98502626d8407045a4e082797682ba56b
+Author: Christian Glusa <caglusa@sandia.gov>
+Date:   Fri Jul 3 18:02:27 2020 -0600
+
+    Teuchos Comm test: remove duplicate 'using ...'
+
+diff --git a/packages/teuchos/comm/test/Comm/reduce.cpp b/packages/teuchos/comm/test/Comm/reduce.cpp
+index c05ebc0dc34..eac1975ef83 100644
+--- a/packages/teuchos/comm/test/Comm/reduce.cpp
++++ b/packages/teuchos/comm/test/Comm/reduce.cpp
+@@ -53,9 +53,6 @@ bool
+ testReduceSum (bool& success, std::ostream& out,
+                const int root, const Teuchos::Comm<int>& comm)
+ {
+-#ifdef HAVE_TEUCHOS_MPI
+-  using Teuchos::MpiComm;
+-#endif // HAVE_TEUCHOS_MPI
+   using Teuchos::reduce;
+   using Teuchos::TypeNameTraits;
+   using std::endl;
+diff --git a/packages/teuchos/comm/test/Comm/scatter.cpp b/packages/teuchos/comm/test/Comm/scatter.cpp
+index 0ca961d2846..001009029c4 100644
+--- a/packages/teuchos/comm/test/Comm/scatter.cpp
++++ b/packages/teuchos/comm/test/Comm/scatter.cpp
+@@ -53,9 +53,6 @@ bool
+ testScatter (bool& success, std::ostream& out,
+              const int root, const Teuchos::Comm<int>& comm)
+ {
+-#ifdef HAVE_TEUCHOS_MPI
+-  using Teuchos::MpiComm;
+-#endif // HAVE_TEUCHOS_MPI
+   using Teuchos::scatter;
+   using Teuchos::TypeNameTraits;
+   using std::endl;