[k2] add extra flex pic version with libc++ usage for runtime-light (#1475)

Author: astrophysik

flex/flex.cmake

@@ -25,8 +25,13 @@ vk_add_library_no_pic(flex-data-src-no-pic OBJECT ${FLEX_SOURCES})
 add_dependencies(flex-data-src-no-pic flex-data)
 
 if (COMPILE_RUNTIME_LIGHT)
-    target_compile_options(flex-data-src-pic PUBLIC -stdlib=libc++ ${RUNTIME_LIGHT_VISIBILITY})
-    target_link_options(flex-data-src-pic PUBLIC -stdlib=libc++)
+    # A new pic library needs to be added because it uses libc++.
+    # vkext is not ready to use a library with libc++.
+    vk_add_library_pic(flex-libcpp-data-src-pic OBJECT ${FLEX_SOURCES})
+    add_dependencies(flex-libcpp-data-src-pic flex-data)
+
+    target_compile_options(flex-libcpp-data-src-pic PUBLIC -stdlib=libc++ ${RUNTIME_LIGHT_VISIBILITY})
+    target_link_options(flex-libcpp-data-src-pic PUBLIC -stdlib=libc++)
 endif()
 
 vk_add_library_pic(flex_data_shared-pic SHARED $<TARGET_OBJECTS:flex-data-src-pic>)

runtime-light/runtime-light.cmake

@@ -63,7 +63,7 @@ set(RUNTIME_LIGHT_LINK_LIBS "${KPHP_TIMELIB_PIC_LIBRARIES} ${PCRE2_PIC_LIBRARIES
 vk_add_library_pic(kphp-light-runtime-pic STATIC)
 target_compile_options(kphp-light-runtime-pic PUBLIC ${RUNTIME_LIGHT_COMPILE_FLAGS})
 target_link_options(kphp-light-runtime-pic PUBLIC ${RUNTIME_LIGHT_LINK_FLAGS})
-target_link_libraries(kphp-light-runtime-pic PUBLIC vk::pic::flex-data-src vk::pic::light-common vk::pic::unicode vk::pic::runtime-light vk::pic::runtime-common)
+target_link_libraries(kphp-light-runtime-pic PUBLIC vk::pic::flex-libcpp-data-src-pic vk::pic::light-common vk::pic::unicode vk::pic::runtime-light vk::pic::runtime-common)
 
 set_target_properties(kphp-light-runtime-pic PROPERTIES LIBRARY_OUTPUT_NAME libkphp-light-runtime.a)