+eigen.tuxfamily.org (#439)

* eigen.tuxfamily.org built

* Should pass CI, cleaned up package.yaml

* tweaks

* wip

---------

Co-authored-by: Max Howell <mxcl@me.com>

projects/eigen.tuxfamily.org/package.yml

@@ -0,0 +1,56 @@
+distributable:
+  url: https://gitlab.com/libeigen/eigen/-/archive/{{version}}/eigen-{{version}}.tar.gz
+  strip-components: 1
+
+versions:
+  - 3.4.0
+
+build:
+  working-directory: build
+  dependencies:
+    tea.xyz/gx/cc: c99
+    tea.xyz/gx/make: '*'
+    cmake.org: '^3'
+  script: |
+    cmake .. -DCMAKE_INSTALL_PREFIX={{prefix}}
+    make install
+
+    # stuff expects `Eigen` to be in `include` rather than namespaced
+    cd "{{prefix}}"
+    mv include/eigen3/* include
+    cd include
+    rmdir eigen3
+    # but work for stuff that expects the namespace too
+    ln -s eigen3 .
+  test:
+    make test
+
+test:
+  dependencies:
+    tea.xyz/gx/cc: c99
+    freedesktop.org/pkg-config: ^0.29
+  env:
+    cxxflags: $(pkg-config --cflags eigen3)
+  fixture: |
+    #include <iostream>
+    #include <Eigen/Dense>
+    using Eigen::MatrixXd;
+    int main()
+    {
+      MatrixXd m(2,2);
+      m(0,0) = 3;
+      m(1,0) = 2.5;
+      m(0,1) = -1;
+      m(1,1) = m(1,0) + m(0,1);
+      std::cout << m << std::endl;
+    }
+  script: |
+    mv $FIXTURE test.cpp
+    g++ test.cpp ${cxxflags} -o test
+    ./test > output.txt
+    out=$(./test)
+    if test "$out" = $'  3  -1\n2.5 1.5'; then
+      echo "PASS"
+    else
+      echo "FAIL"
+    fi