--- lib/core/include/internal/pool_allocator.h.orig	2020-02-19 02:55:20.000000000 -0700
+++ lib/core/include/internal/pool_allocator.h	2020-02-19 20:30:07.385673716 -0700
@@ -33,15 +33,15 @@ namespace pm {
 class allocator : public PM_ALLOCATOR_BASE<char> {
    using base_t = PM_ALLOCATOR_BASE<char>;
 public:
-   void* allocate(size_t n)
+   void* allocate(std::size_t n)
    {
       return base_t::allocate(n, nullptr);
    }
-   void deallocate(void* p, size_t n)
+   void deallocate(void* p, std::size_t n)
    {
       base_t::deallocate(reinterpret_cast<char*>(p), n);
    }
-   void* reallocate(void* p, size_t old_sz, size_t new_sz);
+   void* reallocate(void* p, std::size_t old_sz, std::size_t new_sz);
 
    template <typename Data, typename... Args>
    Data* construct(Args&&... args)
--- lib/core/src/lib_init.cc.orig	2020-02-19 02:55:20.000000000 -0700
+++ lib/core/src/lib_init.cc	2020-02-19 20:30:07.386673716 -0700
@@ -17,6 +17,7 @@
 
 #include "polymake/internal/pool_allocator.h"
 
+#include <cstddef>
 #include <cstring>
 #include <memory>
 #include <cstdlib>
@@ -24,7 +25,7 @@
 #include <gmp.h>
 
 extern "C" {
-   void* __gmp_default_allocate(size_t);
+   void* __gmp_default_allocate(std::size_t);
 }
 
 namespace pm {
@@ -36,19 +37,19 @@ namespace {
 
 class pool_allocator_constants : public __gnu_cxx::__pool_alloc_base {
 public:
-   static constexpr size_t align = _S_align, limit = _S_max_bytes;
+   static constexpr std::size_t align = _S_align, limit = _S_max_bytes;
 };
 
 }
 
-void* pm::allocator::reallocate(void* p, size_t old_sz, size_t new_sz)
+void* pm::allocator::reallocate(void* p, std::size_t old_sz, std::size_t new_sz)
 {
    if (!p) {
       assert(old_sz == 0);
       return allocate(new_sz);
    }
    static const bool use_new = getenv("GLIBCPP_FORCE_NEW") || getenv("GLIBCXX_FORCE_NEW");
-   constexpr size_t align_mask = pool_allocator_constants::align-1;
+   constexpr std::size_t align_mask = pool_allocator_constants::align-1;
    if (!use_new && ((old_sz+align_mask) & ~align_mask) == ((new_sz+align_mask) & ~align_mask) && new_sz < pool_allocator_constants::limit)
       return p;
    void* new_p = allocate(new_sz);
@@ -61,7 +62,7 @@ void* pm::allocator::reallocate(void* p,
 
 #else  // libc++
 
-void* pm::allocator::reallocate(void* p, size_t old_sz, size_t new_sz)
+void* pm::allocator::reallocate(void* p, std::size_t old_sz, std::size_t new_sz)
 {
    void* new_p = allocate(new_sz);
    if (new_p) {
@@ -76,16 +77,16 @@ void* pm::allocator::reallocate(void* p,
 namespace {
 
 allocator gmp_allocator;
-void* pm_gmp_allocate(size_t n) { return gmp_allocator.allocate(n); }
-void pm_gmp_deallocate(void* p, size_t n) { gmp_allocator.deallocate(p, n); }
-void* pm_gmp_reallocate(void* p, size_t old_sz, size_t new_sz) { return gmp_allocator.reallocate(p, old_sz, new_sz); }
+void* pm_gmp_allocate(std::size_t n) { return gmp_allocator.allocate(n); }
+void pm_gmp_deallocate(void* p, std::size_t n) { gmp_allocator.deallocate(p, n); }
+void* pm_gmp_reallocate(void* p, std::size_t old_sz, std::size_t new_sz) { return gmp_allocator.reallocate(p, old_sz, new_sz); }
 
 void init_gmp_memory_management() __attribute__((constructor));
 
 void init_gmp_memory_management()
 {
    // switch to custom GMP allocators only if no other component did it before
-   typedef void* (*alloc_t)(size_t);
+   typedef void* (*alloc_t)(std::size_t);
    alloc_t was_alloc;
    mp_get_memory_functions(&was_alloc, nullptr, nullptr);
    if (was_alloc == &__gmp_default_allocate)