perf tui: Add explicit -lslang option

At least on rawhide using -lnewt is not enough if we use SLang routines
directly, so add an explicit -lslang since we use SLang routines.

Reported-by: Ingo Molnar <mingo@elte.hu>
Tested-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/Makefile b/tools/perf/Makefile
index a9281cc..e2729fc 100644
--- a/tools/perf/Makefile
+++ b/tools/perf/Makefile
@@ -564,7 +564,7 @@
 else
 	# Fedora has /usr/include/slang/slang.h, but ubuntu /usr/include/slang.h
 	BASIC_CFLAGS += -I/usr/include/slang
-	EXTLIBS += -lnewt
+	EXTLIBS += -lnewt -lslang
 	LIB_OBJS += $(OUTPUT)util/newt.o
 endif