Use system's tinycbor instead of vendoring it in
diff -rupN a/c2rust-ast-exporter/build.rs b/c2rust-ast-exporter/build.rs
--- a/c2rust-ast-exporter/build.rs	2023-05-22 22:14:35.000000000 +0200
+++ b/c2rust-ast-exporter/build.rs	2024-01-06 22:54:06.039088094 +0100
@@ -142,7 +142,7 @@ fn build_native(llvm_info: &LLVMInfo) {
     };
 
     // Statically link against 'clangAstExporter' which requires 'tinycbor'
-    println!("cargo:rustc-link-lib=static=tinycbor");
+    println!("cargo:rustc-link-lib=dylib=tinycbor");
     println!("cargo:rustc-link-lib=static=clangAstExporter");
 
     println!("cargo:rustc-link-search=native={}", llvm_lib_dir);
diff -rupN a/c2rust-ast-exporter/src/CMakeLists.txt b/c2rust-ast-exporter/src/CMakeLists.txt
--- a/c2rust-ast-exporter/src/CMakeLists.txt	2023-05-22 22:14:35.000000000 +0200
+++ b/c2rust-ast-exporter/src/CMakeLists.txt	2024-01-06 22:55:39.124799597 +0100
@@ -5,14 +5,9 @@ project(ASTExporter)
 # TinyCBOR                                      #
 #################################################
 
-set(TINYCBOR_REPO "https://github.com/intel/tinycbor.git" CACHE STRING "tinycbor git repo URL")
-
-# v0.6.3 tag, but using the commit hash instead (of the tarball hash) for integrity checks
-# unlike a .tar.gz MD5 hash, this SHA-1 commit hash should stay stable regardless of compression/archiving
-# (GitHub has changed this), and still retains the integrity check
-set(TINYCBOR_TAG "d393c16f3eb30d0c47e6f9d92db62272f0ec4dc7" CACHE STRING "tinycbor git tag/branch/commit hash")
-
-set(TINYCBOR_PREFIX "${CMAKE_BINARY_DIR}/tinycbor" CACHE STRING "tinycbor install prefix")
+include(FindPkgConfig)
+pkg_search_module(TINYCBOR REQUIRED tinycbor)
+include_directories(${TINYCBOR_INCLUDE_DIRS})
 
 if(CMAKE_SYSTEM_NAME STREQUAL "FreeBSD")
     set(MAKE "gmake")
@@ -20,29 +15,6 @@ else()
     set(MAKE "make")
 endif()
 
-include(ExternalProject)
-ExternalProject_Add(tinycbor_build
-            PREFIX ${TINYCBOR_PREFIX}
-            INSTALL_DIR ${CMAKE_BINARY_DIR}
-            GIT_REPOSITORY ${TINYCBOR_REPO}
-            GIT_TAG ${TINYCBOR_TAG}
-            # the fd redirection here fails when the build run inside Cargo.
-            # patch from upstream:
-            # https://github.com/intel/tinycbor/commit/6176e0a28d7c5ef3a5e9cbd02521999c412de72c
-            PATCH_COMMAND patch --forward -p1 < ${CMAKE_CURRENT_SOURCE_DIR}/tinycbor_fix_build.patch || true
-            CONFIGURE_COMMAND ${MAKE} .config && cat ${CMAKE_CURRENT_SOURCE_DIR}/tinycbor.config >> .config
-            BUILD_COMMAND ${MAKE} --quiet prefix=<INSTALL_DIR> CFLAGS=-fPIC
-            INSTALL_COMMAND ${MAKE} --quiet prefix=<INSTALL_DIR> install
-            BUILD_IN_SOURCE 1
-            BUILD_BYPRODUCTS ${CMAKE_BINARY_DIR}/lib/libtinycbor.a
-)
-
-include_directories(${CMAKE_BINARY_DIR}/include)
-
-add_library(tinycbor STATIC IMPORTED)
-set_target_properties(tinycbor PROPERTIES IMPORTED_LOCATION ${CMAKE_BINARY_DIR}/lib/libtinycbor.a)
-add_dependencies(tinycbor tinycbor_build)
-
 set(AST_EXPORTER_SRCS
   AstExporter.cpp
   FloatingLexer.cpp