cmake: Make output_target_map more robust (fixes #6208)

This PR refactors the old output_target_map, which was a
raw dict, into it's own class. This makes the access to
the map more uniform and robust (at the cost of more lines
of code).

Additionally relative paths to the build directory are
now also tracked for outputs. This is neccessary to
corretcly distingluish files with the same name, that are
in different directories.

1 files changed, 5 insertions, 0 deletions

diff --git a/test cases/cmake/8 custom command/subprojects/cmMod/cpyNext.cpp.am b/test cases/cmake/8 custom command/subprojects/cmMod/cpyNext.cpp.am
new file mode 100644
index 000000000..20a8815ae
--- /dev/null
+++ b/test cases/cmake/8 custom command/subprojects/cmMod/cpyNext.cpp.am
@@ -0,0 +1,5 @@
+#include "cpyNext.hpp"
+
+std::string getStrNext() {
+  return "Hello Copied File -- now even more convoluted!";
+}