libbsdl: scaffold + working BSDL parser (struct + JSON, C ABI)

Standalone LGPL-2.1 parser for BSDL (IEEE 1149.1), shared by essim and
bs_explorer. The parser is ported from the Viveris JTAG Core loader,
decoupled from jtag_core, and extended with two extractions the original
lacks:
  - PIN_MAP_STRING -> per-port physical package pin, scalar and vector;
  - TAP_SCAN_*     -> TAP signal roles (TDI/TDO/TMS/TCK/TRST).

Exposes a stable C ABI (bsdl_parse_file/buffer -> bsdl_t, bsdl_to_json)
with a dependency-free JSON serializer and a bsdl2json CLI. CMake builds a
versioned shared library with install/export rules for find_package(bsdl).

Verified against m2gl010t, xcku040 and xcku15p (100% pin mapping, correct
IDCODEs and TAP roles); api and parse regression tests pass, clean build.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

CMakeLists.txt

@@ -0,0 +1,109 @@
+cmake_minimum_required(VERSION 3.14)
+
+project(bsdl
+  LANGUAGES C
+  VERSION 0.1.0
+  DESCRIPTION "Standalone BSDL (IEEE 1149.1) parser — struct + JSON, stable C ABI"
+)
+
+# --- top-level detection (PROJECT_IS_TOP_LEVEL needs CMake >= 3.21) ---
+if(NOT DEFINED PROJECT_IS_TOP_LEVEL)
+  if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
+    set(PROJECT_IS_TOP_LEVEL ON)
+  else()
+    set(PROJECT_IS_TOP_LEVEL OFF)
+  endif()
+endif()
+
+# This is a dynamic library by nature; build shared unless told otherwise.
+if(NOT DEFINED BUILD_SHARED_LIBS)
+  set(BUILD_SHARED_LIBS ON)
+endif()
+
+option(BSDL_BUILD_CLI   "Build the bsdl2json command-line tool" ON)
+option(BSDL_BUILD_TESTS "Build the test suite"                  ${PROJECT_IS_TOP_LEVEL})
+
+# ---------------------------------------------------------------- library ----
+add_library(bsdl
+  src/bsdl.c
+  src/bsdl_parse.c
+  src/bsdl_strings.c
+  src/bsdl_json.c
+)
+add_library(bsdl::bsdl ALIAS bsdl)
+
+target_include_directories(bsdl
+  PUBLIC
+    $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
+    $<INSTALL_INTERFACE:include>
+  PRIVATE
+    ${CMAKE_CURRENT_SOURCE_DIR}/src
+)
+
+set_target_properties(bsdl PROPERTIES
+  C_STANDARD 11
+  C_STANDARD_REQUIRED ON
+  C_VISIBILITY_PRESET hidden
+  VISIBILITY_INLINES_HIDDEN ON
+  VERSION   ${PROJECT_VERSION}
+  SOVERSION ${PROJECT_VERSION_MAJOR}
+  PUBLIC_HEADER ${CMAKE_CURRENT_SOURCE_DIR}/include/bsdl/bsdl.h
+)
+
+# Mark exported symbols (dllexport on Windows; default-visibility on ELF).
+if(BUILD_SHARED_LIBS)
+  target_compile_definitions(bsdl PRIVATE BSDL_BUILD_SHARED)
+endif()
+
+if(CMAKE_C_COMPILER_ID MATCHES "GNU|Clang")
+  target_compile_options(bsdl PRIVATE -Wall -Wextra -Wpedantic)
+endif()
+
+# -------------------------------------------------------------------- CLI ----
+if(BSDL_BUILD_CLI)
+  add_executable(bsdl2json tools/bsdl2json.c)
+  target_link_libraries(bsdl2json PRIVATE bsdl)
+endif()
+
+# ------------------------------------------------------------------ tests ----
+if(BSDL_BUILD_TESTS)
+  enable_testing()
+  add_subdirectory(tests)
+endif()
+
+# --------------------------------------------------- install / export -------
+include(GNUInstallDirs)
+include(CMakePackageConfigHelpers)
+
+install(TARGETS bsdl
+  EXPORT bsdlTargets
+  LIBRARY       DESTINATION ${CMAKE_INSTALL_LIBDIR}
+  ARCHIVE       DESTINATION ${CMAKE_INSTALL_LIBDIR}
+  RUNTIME       DESTINATION ${CMAKE_INSTALL_BINDIR}
+  PUBLIC_HEADER DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/bsdl
+)
+if(BSDL_BUILD_CLI)
+  install(TARGETS bsdl2json RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
+endif()
+
+install(EXPORT bsdlTargets
+  FILE      bsdlTargets.cmake
+  NAMESPACE bsdl::
+  DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/bsdl
+)
+
+configure_package_config_file(
+  ${CMAKE_CURRENT_SOURCE_DIR}/cmake/bsdlConfig.cmake.in
+  ${CMAKE_CURRENT_BINARY_DIR}/bsdlConfig.cmake
+  INSTALL_DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/bsdl
+)
+write_basic_package_version_file(
+  ${CMAKE_CURRENT_BINARY_DIR}/bsdlConfigVersion.cmake
+  VERSION       ${PROJECT_VERSION}
+  COMPATIBILITY SameMajorVersion
+)
+install(FILES
+  ${CMAKE_CURRENT_BINARY_DIR}/bsdlConfig.cmake
+  ${CMAKE_CURRENT_BINARY_DIR}/bsdlConfigVersion.cmake
+  DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/bsdl
+)