--- firefox-52.9.0esr/tools/profiler/core/platform.h~	2020-03-03 13:20:04.000000000 +0100
+++ firefox-52.9.0esr/tools/profiler/core/platform.h	2020-03-03 13:20:47.438599518 +0100
@@ -63,6 +63,7 @@
 // provide a wrapper for it (except for Bionic)
 #if defined(__linux__)
 #include <unistd.h>
+#if !__GLIBC_PREREQ(2, 30)
 #if !defined(__BIONIC__)
 #include <sys/syscall.h>
 static inline pid_t gettid()
@@ -71,6 +72,7 @@ static inline pid_t gettid()
 }
 #endif
 #endif
+#endif
 
 #ifdef XP_WIN
 #include <windows.h>