PrusaSlicer: fix musl build

srcpkgs/PrusaSlicer/patches/0002-Replace-get_current_thread_name-for-musl.patch

@@ -0,0 +1,30 @@
+--- src/libslic3r/Thread.cpp.orig	2021-01-24 13:50:00.469444149 +0100
++++ src/libslic3r/Thread.cpp	2021-01-24 13:51:17.109443201 +0100
+@@ -171,16 +171,27 @@ bool set_thread_name(boost::thread &thre
+ 	return true;
+ }
+ 
++#ifndef __GLIBC__
++thread_local char current_thread_name[16] = { 0 };
++#endif
++
+ bool set_current_thread_name(const char *thread_name)
+ {
++#ifndef __GLIBC__
++	strncpy(current_thread_name, thread_name, 15);
++#endif
+ 	pthread_setname_np(pthread_self(), thread_name);
+ 	return true;
+ }
+ 
+ std::optional<std::string> get_current_thread_name()
+ {
++#ifdef __GLIBC__
+ 	char buf[16];
+ 	return std::string(pthread_getname_np(pthread_self(), buf, 16) == 0 ? buf : "");
++#else
++	return std::string(current_thread_name);
++#endif
+ }
+ 
+ #endif