Fix position independent code on Linux. (#941)

Former-commit-id: e21aa88a8b2b59caa2215c15be7df2a809534208

cmake/libigl.cmake

@@ -87,6 +87,11 @@ if(BUILD_SHARED_LIBS)
   set_target_properties(igl_common PROPERTIES INTERFACE_POSITION_INDEPENDENT_CODE ON)
 endif()
 
+if(UNIX)
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fPIC")
+  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fPIC")
+endif()
+
 # Eigen
 if(TARGET Eigen3::Eigen)
   # If an imported target already exists, use it

python/CMakeLists.txt

@@ -16,7 +16,7 @@ find_package(PythonLibs REQUIRED)
 
 string(TOUPPER "${CMAKE_BUILD_TYPE}" U_CMAKE_BUILD_TYPE)
 if(UNIX)
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -fPIC")
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fPIC")
   set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fPIC")
   if(NOT ${U_CMAKE_BUILD_TYPE} MATCHES DEBUG)
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fvisibility=hidden -flto")