Set '-fPIC' the correct way

Author: yim-lee

CMakeLists.txt

@@ -17,9 +17,6 @@ list(APPEND CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR}/cmake/modules)
 
 include(SwiftSupport)
 
-# Fixes error: "requires dynamic R_X86_64_PC32 reloc against 'XXX' which may overflow at runtime"
-set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fPIC")
-
 if(CMAKE_VERSION VERSION_LESS 3.16 AND CMAKE_SYSTEM_NAME STREQUAL Windows)
   set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
   set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
@@ -34,6 +31,10 @@ if(CMAKE_SYSTEM_NAME STREQUAL Windows OR CMAKE_SYSTEM_NAME STREQUAL Darwin)
   option(BUILD_SHARED_LIBS "Build shared libraries by default" YES)
 endif()
 
+if(BUILD_SHARED_LIBS)
+  set(CMAKE_POSITION_INDEPENDENT_CODE YES)
+endif()
+
 if(APPLE)
   find_library(CRYPTO_KIT CryptoKit)
   if(NOT CRYPTO_KIT)