icetime: Add generated timings-*.cc files to .gitignore and make clean

icetime/.gitignore

diff --git a/icetime/.gitignore b/icetime/.gitignore
index 5c1b012..70d5a6b 100644
--- a/icetime/.gitignore
+++ b/icetime/.gitignore
@@ -1,6 +1,7 @@
 icetime
 icetime.exe
 timings.inc
+timings-*.cc
 test[0-9]*
 *.d
 *.o

icetime/Makefile

diff --git a/icetime/Makefile b/icetime/Makefile
index 6d9ac4f..38e2fe6 100644
--- a/icetime/Makefile
+++ b/icetime/Makefile
@@ -65,7 +65,7 @@
 show: show0 show1 show2 show3 show4 show5 show6 show7 show8 show9
 
 clean:
-	rm -f icetime$(EXE) icetime.exe *.o *.d
+	rm -f icetime$(EXE) icetime.exe *.o *.d timings-*.cc
 	rm -rf test[0-9]*
 
 -include *.d