chore: tweak cmakelists and fetch clipper2

CMakeLists.txt

@@ -4,6 +4,11 @@ project(clipper2c LANGUAGES CXX)
 set(CMAKE_VERBOSE_MAKEFILE ON)
 set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 
+# turn off unused parts of Clipper2
+set(CLIPPER2_TESTS OFF)
+set(CLIPPER2_EXAMPLES OFF)
+set(CLIPPER2_UTILS OFF)
+
 option(BUILD_SHARED_LIBS ON)
 
 add_compile_options(-fPIC)
@@ -13,6 +18,8 @@ add_subdirectory(vendor/Clipper2/CPP)
 file(GLOB_RECURSE SOURCE_FILES  src/*.cpp)
 file(GLOB_RECURSE INCLUDE_FILES include/*.h) 
 
+set(PCFILE "${CMAKE_CURRENT_BINARY_DIR}/clipper2c.pc")
+
 add_library(clipper2c SHARED ${INCLUDE_FILES} ${SOURCE_FILES})
 
 target_link_libraries(
@@ -29,8 +36,13 @@ set_target_properties(clipper2c PROPERTIES FOLDER Libraries
                                 PUBLIC_HEADER "${INCLUDE_FILES}"
 )
 
+
+CONFIGURE_FILE(clipper2c.pc.cmakein "${PCFILE}" @ONLY)
+
 install(TARGETS clipper2c
         PUBLIC_HEADER DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/clipper2c
 )
 
+install(FILES ${PCFILE} DESTINATION ${CMAKE_INSTALL_LIBDIR}/pkgconfig)
+
 target_compile_features(clipper2c PUBLIC cxx_std_17)

clipper2c.pc.cmakein

@@ -0,0 +1,12 @@
+prefix=@CMAKE_INSTALL_PREFIX@
+exec_prefix=${prefix}
+libdir=${prefix}/@CMAKE_INSTALL_LIBDIR@
+includedir=${prefix}/@CMAKE_INSTALL_INCLUDEDIR@
+
+Name: clipper2c@PCFILE_LIB_SUFFIX@
+Description: C warpper of a Polygon Clipping and Offsetting library in C++
+Version: @PROJECT_VERSION@
+URL: https://github.com/epit3d/clipper2c
+Requires:
+Libs: -L${libdir} -lclipper2c@PCFILE_LIB_SUFFIX@
+Cflags: -I${includedir}