Silence two valgrind warnings in libdl and forkfd

kde.supp

@@ -26,6 +26,13 @@
     fun:_dl_catch_error*
 }
 
+{
+    addr8/dl_catch_error
+    MemCheck:Addr8
+    ...
+    fun:_dl_catch_error*
+}
+
 {
     strchr/libc/_dl_catch_error
     MemCheck:Cond
@@ -179,6 +186,15 @@
    fun:inflateInit2*
 }
 
+# Qt uses the waitid syscall in strange ways, to detect forkfd support
+{
+   sys_waitid from qtbase/src/3rdparty/forkfd/forkfd_linux.c
+   Memcheck:Param
+   waitid(infop)
+   fun:syscall
+   fun:_ZL10sys_waitidiiP9siginfo_tiP6rusage
+}
+
 # Leakcheck suppressions
 {
    dlopen_worker_malloc