Add fortran test with an install:yes static library

This adds a test which makes use of an install:yes static library that
depends on another static library. This triggers a promotion to
link_whole_target inside meson which takes different code paths in
certain places.

Also makes use of .F90 source (capital F) to test for case
(in)sensitivity.

test cases/fortran/21 install static/main.f90

@@ -0,0 +1,4 @@
+use main_lib
+implicit none
+call main_hello()
+end program

test cases/fortran/21 install static/main_lib.f90

@@ -0,0 +1,16 @@
+module main_lib
+    
+  use static_hello
+  implicit none
+
+  private
+  public :: main_hello
+
+  contains
+
+  subroutine main_hello
+    call static_say_hello()
+    print *, "Main hello routine finished."
+  end subroutine main_hello
+
+end module main_lib

test cases/fortran/21 install static/meson.build

@@ -0,0 +1,20 @@
+# Based on 'fortran/5 static', but:
+#   - Uses a subproject dependency
+#   - Is an install:true static library to trigger certain codepath (promotion to link_whole)
+#   - Does fortran code 'generation' with configure_file
+#   - Uses .F90 ext (capital F typically denotes a dependence on preprocessor treatment, which however is not used)
+project('try-static-subproject-dependency', 'fortran', default_options: ['default_library=static'])
+
+static_dep = dependency('static_hello', fallback: ['static_hello', 'static_hello_dep'])
+
+mainsrc = 'main_lib.f90'
+mainsrc = configure_file(
+    command: [find_program('cp'), '@INPUT@', '@OUTPUT@'],
+    input: mainsrc,
+    output: 'main_lib_output.F90'
+)
+main_lib = library('mainstatic', mainsrc, dependencies: static_dep, install: true)
+main_dep = declare_dependency(link_with: main_lib)
+
+main_exe = executable('main_exe', 'main.f90', dependencies: main_dep)
+test('static_subproject_test', main_exe)

test cases/fortran/21 install static/subprojects/static_hello/meson.build

@@ -0,0 +1,12 @@
+project('static-hello', 'fortran')
+
+# staticlibsource = 'static_hello.f90'
+staticlibsource = configure_file(
+    command: [find_program('cp'), '@INPUT@', '@OUTPUT@'],
+    input: 'static_hello.f90',
+    output: 'static_hello_output.F90'
+)
+
+static_hello_lib = static_library('static_hello', staticlibsource, install: false)
+
+static_hello_dep = declare_dependency(link_with: static_hello_lib)

test cases/fortran/21 install static/subprojects/static_hello/static_hello.f90

@@ -0,0 +1,17 @@
+module static_hello
+implicit none
+
+private
+public :: static_say_hello
+
+interface static_say_hello
+  module procedure say_hello
+end interface static_say_hello
+
+contains
+
+subroutine say_hello
+  print *, "Static library called."
+end subroutine say_hello
+
+end module static_hello

test cases/fortran/21 install static/test.json

@@ -0,0 +1,5 @@
+{
+    "installed": [
+        {"file": "usr/lib/libmainstatic.a", "type": "file"}
+    ]
+}