Move dead submodules in-tree

Signed-off-by: swurl <swurl@swurl.xyz>

externals/sirit/src/CMakeLists.txt

@@ -0,0 +1,32 @@
+add_library(sirit
+    ../include/sirit/sirit.h
+    sirit.cpp
+    stream.h
+    common_types.h
+    instructions/type.cpp
+    instructions/constant.cpp
+    instructions/function.cpp
+    instructions/flow.cpp
+    instructions/debug.cpp
+    instructions/derivatives.cpp
+    instructions/memory.cpp
+    instructions/annotation.cpp
+    instructions/misc.cpp
+    instructions/logical.cpp
+    instructions/conversion.cpp
+    instructions/bit.cpp
+    instructions/arithmetic.cpp
+    instructions/extension.cpp
+    instructions/image.cpp
+    instructions/group.cpp
+    instructions/barrier.cpp
+    instructions/atomic.cpp
+)
+
+target_compile_options(sirit PRIVATE ${SIRIT_CXX_FLAGS})
+
+target_include_directories(sirit
+                           PUBLIC ../include
+                           PRIVATE .)
+
+target_link_libraries(sirit PUBLIC SPIRV-Headers::SPIRV-Headers)