diff --git a/.gitignore b/.gitignore
index 52ed47c..6912295 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,3 +3,5 @@ docs/out/
 .*/
 *~
 *.bak
+*.sh
+.clangd
\ No newline at end of file
diff --git a/include/calico/system/thread.h b/include/calico/system/thread.h
index c383bc4..12a9d17 100644
--- a/include/calico/system/thread.h
+++ b/include/calico/system/thread.h
@@ -135,6 +135,10 @@ void threadPrepare(Thread* t, ThreadFunc entrypoint, void* arg, void* stack_top,
 //! @brief Returns the required size for thread-local storage (8-byte aligned) @see threadAttachLocalStorage
 size_t threadGetLocalStorageSize(void);
 
+// Sets an extra amount of thread-local storage to be allocated for threads created using
+// system calls (POSIX threads, C threads, C++ std::thread). Will be 8-byte aligned.
+void threadSetPthreadExtraTls(const size_t size);
+
 /*! @brief Attaches thread-local storage to a @ref Thread @p t
 	@param[in] storage 8-byte aligned memory buffer to use as thread-local storage,
 	or NULL to consume thread stack memory instead
diff --git a/source/system/newlib_syscalls.c b/source/system/newlib_syscalls.c
index 3231907..c491862 100644
--- a/source/system/newlib_syscalls.c
+++ b/source/system/newlib_syscalls.c
@@ -133,6 +133,14 @@ int __SYSCALL(cond_wait_recursive)(_COND_T* cond, _LOCK_RECURSIVE_T* lock, uint6
 	return 0;
 }
 
+static size_t extraTls = 0;
+
+void threadSetPthreadExtraTls(const size_t size)
+{
+	// make sure it's 8-byte aligned
+	extraTls = (size + 7) &~ 7;
+}
+
 int __SYSCALL(thread_create)(struct __pthread_t** thread, void* (*func)(void*), void* arg, void* stack_addr, size_t stack_size)
 {
 	if (((uptr)stack_addr & 7) || (stack_size & 7)) {
@@ -145,7 +153,7 @@ int __SYSCALL(thread_create)(struct __pthread_t** thread, void* (*func)(void*),
 
 	size_t struct_sz = (sizeof(struct __pthread_t) + 7) &~ 7;
 
-	size_t needed_sz = struct_sz + threadGetLocalStorageSize();
+	size_t needed_sz = struct_sz + threadGetLocalStorageSize() + extraTls;
 	if (!stack_addr) {
 		needed_sz += stack_size;
 	}