Update: hello_complex example with sub directory

To demonstrate and test recursive source file discovery.

Author: LKedward

test/example_packages/hello_complex/source/farewell_m.f90

@@ -1,4 +1,5 @@
 module farewell_m
+    use subdir_constants, only: FAREWELL_STR
     implicit none
     private
 
@@ -8,6 +9,6 @@ function make_farewell(name) result(greeting)
         character(len=*), intent(in) :: name
         character(len=:), allocatable :: greeting
 
-        greeting = "Goodbye, " // name // "!"
+        greeting = FAREWELL_STR // name // "!"
     end function make_farewell
 end module farewell_m

test/example_packages/hello_complex/source/greet_m.f90

@@ -1,4 +1,5 @@
 module greet_m
+    use subdir_constants, only: GREET_STR
     implicit none
     private
 
@@ -8,6 +9,6 @@ function make_greeting(name) result(greeting)
         character(len=*), intent(in) :: name
         character(len=:), allocatable :: greeting
 
-        greeting = "Hello, " // name // "!"
+        greeting = GREET_STR // name // "!"
     end function make_greeting
 end module greet_m

test/example_packages/hello_complex/source/subdir/constants.f90

@@ -0,0 +1,7 @@
+module subdir_constants
+implicit none
+
+character(*), parameter :: GREET_STR = 'Hello, '
+character(*), parameter :: FAREWELL_STR = 'Goodbye, '
+
+end module subdir_constants