create simple test program

Author: perazz

example_packages/preprocess_per_dependency/app/main.f90

@@ -0,0 +1,8 @@
+program hello_fpm
+    use utils, only: say_hello
+    integer :: ierr
+
+    call say_hello(ierr)
+    stop ierr ! ierr==0 if DEPENDENCY_MACRO is defined
+
+end program hello_fpm

example_packages/preprocess_per_dependency/crate/utils/fpm.toml

@@ -0,0 +1,5 @@
+name = "utils"
+
+[preprocess]
+[preprocess.cpp]
+macros = ["X=1"]

example_packages/preprocess_per_dependency/crate/utils/src/say_hello.f90

@@ -0,0 +1,19 @@
+module utils
+
+    implicit none
+    
+contains
+
+    subroutine say_hello(ierr)
+        integer, intent(out) :: ierr
+
+        ierr = -1
+#ifdef DEPENDENCY_MACRO
+        ierr = 0
+#endif
+
+        print *, "Dependency macro ", merge(" IS","NOT",ierr==0)," defined" 
+
+    end subroutine say_hello
+
+end module utils

example_packages/preprocess_per_dependency/fpm.toml

@@ -0,0 +1,4 @@
+name = "preprocess_cpp_deps"
+
+[dependencies]
+utils = { path = "crate/utils" , preprocess.cpp="DEPENDENCY_MACRO" }