diff --git a/src/core/sys/posix/stdlib.d b/src/core/sys/posix/stdlib.d
index 3d239469f2..919f57c70f 100644
--- a/src/core/sys/posix/stdlib.d
+++ b/src/core/sys/posix/stdlib.d
@@ -179,6 +179,11 @@ else version( Solaris )
 
     void* valloc(size_t); // LEGACY non-standard
 }
+else version( CRuntime_Musl )
+{
+    int setenv(in char*, in char*, int);
+    int unsetenv(in char*);
+}
 
 //
 // Thread-Safe Functions (TSF)
@@ -493,6 +498,13 @@ else version( CRuntime_Bionic )
     void    srandom(uint s) { srand48(s); }
     int     unlockpt(int);
 }
+else version( CRuntime_Musl )
+{
+    char*  realpath(in char*, char*);
+    int    putenv(char*);
+    int    mkstemp(char*);
+
+}
 else version( Solaris )
 {
     //WNOHANG     (defined in core.sys.posix.sys.wait)