Additional C flags required for static-std.cmake to fix behaviour change in CMake

[oliverdaniell]

CMake behavior has changed from version 3.7 to 3.9 with respect to the handling of static libgcc flags.

Building the example below with a toolchain that include /flags/static-std.cmake will cause cmake to add an additional -lgcc_s -lgcc_s to the link line.

cmake_minimum_required(VERSION 3.0)

# Project
project(static_test C CXX)

add_library(mylib::mylib STATIC IMPORTED)

set_target_properties(mylib::mylib PROPERTIES
  IMPORTED_LINK_INTERFACE_LANGUAGES "C"
  IMPORTED_LOCATION "/path/to/mylib.a"
  )

add_executable(static_test main.cpp)
target_link_libraries(static_test mylib::mylib)

The fix is to add the following line to /flags/static-std.cmake

polly_add_cache_flag(CMAKE_C_FLAGS "-static-libgcc")

[ruslo]

polly_add_cache_flag(CMAKE_C_FLAGS "-static-libgcc")

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