Follow GNU install conventions

- allow customization of install locations by GNUInstallDirs module
- enable project installation on CI testing

Author: awvwgk

Diff for: .github/workflows/CI.yml

@@ -59,7 +59,12 @@ jobs:
           brew link gcc@${GCC_V}
 
     - name: Configure with CMake
-      run: cmake -Wdev -DCMAKE_BUILD_TYPE=Release -DCMAKE_MAXIMUM_RANK=4 -S . -B build
+      run: >-
+        cmake -Wdev
+        -DCMAKE_BUILD_TYPE=Release
+        -DCMAKE_MAXIMUM_RANK=4
+        -DCMAKE_INSTALL_PREFIX=$PWD/_dist
+        -S . -B build
 
     - name: Build and compile
       run: cmake --build build
@@ -72,6 +77,9 @@ jobs:
       run: ctest --parallel --output-on-failure
       working-directory: build
 
+    - name: Install project
+      run: cmake --install build
+
     - name: Test in-tree builds
       if: contains( matrix.gcc_v, '10') # Only test one compiler on each platform
       run: |
@@ -129,7 +137,12 @@ jobs:
       run: pip install --upgrade fypp
 
     - name: Configure with CMake
-      run: cmake -Wdev -DCMAKE_BUILD_TYPE=Release -DCMAKE_MAXIMUM_RANK=4 -S . -B build
+      run: >-
+         cmake -Wdev
+         -DCMAKE_BUILD_TYPE=Release
+         -DCMAKE_MAXIMUM_RANK=4
+         -DCMAKE_INSTALL_PREFIX=$PWD/_dist
+         -S . -B build
 
     - name: Build and compile
       run: cmake --build build
@@ -141,3 +154,6 @@ jobs:
     - name: test
       run: ctest --parallel --output-on-failure
       working-directory: build
+
+    - name: Install project
+      run: cmake --install build

Diff for: .github/workflows/ci_windows.yml

@@ -99,6 +99,7 @@ jobs:
         -DCMAKE_BUILD_TYPE=Debug
         -DCMAKE_Fortran_FLAGS_DEBUG="-Wall -Wextra -Wimplicit-interface -fPIC -g -fcheck=all -fbacktrace"
         -DCMAKE_MAXIMUM_RANK=4
+        -DCMAKE_INSTALL_PREFIX=$PWD/_dist
       env:
         FC: gfortran
         CC: gcc
@@ -120,3 +121,6 @@ jobs:
       with:
         name: WindowsCMakeTestlog
         path: build/Testing/Temporary/LastTest.log
+
+    - name: Install project
+      run: cmake --install build

Diff for: CMakeLists.txt

@@ -2,6 +2,9 @@ cmake_minimum_required(VERSION 3.14.0)
 project(stdlib Fortran)
 enable_testing()
 
+# Follow GNU conventions for installation directories
+include(GNUInstallDirs)
+
 include(${PROJECT_SOURCE_DIR}/cmake/stdlib.cmake)
 
 # --- compiler options
@@ -55,5 +58,5 @@ add_subdirectory(src)
 
 install(EXPORT fortran_stdlib-targets
         NAMESPACE fortran_stdlib::
-        DESTINATION "lib/cmake/fortran_stdlib"
+        DESTINATION "${CMAKE_INSTALL_LIBDIR}/cmake/fortran_stdlib"
 )

Diff for: src/CMakeLists.txt

@@ -64,8 +64,8 @@ add_subdirectory(tests)
 
 install(TARGETS fortran_stdlib
         EXPORT fortran_stdlib-targets
-        RUNTIME DESTINATION bin
-        ARCHIVE DESTINATION lib
-        LIBRARY DESTINATION lib
+        RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}"
+        ARCHIVE DESTINATION "${CMAKE_INSTALL_LIBDIR}"
+        LIBRARY DESTINATION "${CMAKE_INSTALL_LIBDIR}"
 )
-install(DIRECTORY ${LIB_MOD_DIR} DESTINATION include)
+install(DIRECTORY ${LIB_MOD_DIR} DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}")