diff -up firefox-78.2.0/tools/profiler/gecko/nsProfiler.cpp.zconst firefox-78.2.0/tools/profiler/gecko/nsProfiler.cpp
--- firefox-78.2.0/tools/profiler/gecko/nsProfiler.cpp.zconst	2020-09-09 20:29:17.489123431 +0200
+++ firefox-78.2.0/tools/profiler/gecko/nsProfiler.cpp	2020-09-09 20:30:09.544457350 +0200
@@ -523,7 +523,7 @@ nsProfiler::GetProfileDataAsGzippedArray
             stream.opaque = nullptr;
             stream.next_out = (Bytef*)outBuff.Elements();
             stream.avail_out = outBuff.Length();
-            stream.next_in = (z_const Bytef*)aResult.Data();
+            stream.next_in = (Bytef*)aResult.Data();
             stream.avail_in = aResult.Length();
 
             // A windowBits of 31 is the default (15) plus 16 for emitting a