Fix linking failure due to different GCC5 inline semantics
https://bugs.gentoo.org/show_bug.cgi?id=571000

In addition, fix QA warnings caused by passing
an unformatted string to printf().

--- gbsplay-0.0.91/Makefile
+++ gbsplay-0.0.91/Makefile
@@ -35,7 +35,7 @@
 	-predboolothers \
 	-shiftnegative \
 	-shiftimplementation
-GBSCFLAGS  := -Wall -fsigned-char -D_FORTIFY_SOURCE=2
+GBSCFLAGS  := -Wall -fsigned-char -std=gnu89
 GBSLDFLAGS := -Wl,-O1 -lm
 GBSPLAYLDFLAGS :=
 
--- gbsplay-0.0.91/plugout.c
+++ gbsplay-0.0.91/plugout.c
@@ -55,10 +55,10 @@
 {
 	long idx;
 
-	printf(_("Available output plugins:\n\n"));
+	fputs(_("Available output plugins:\n\n"), stdout);
 
 	if (plugouts[0] == NULL) {
-		printf(_("No output plugins available.\n\n"));
+		fputs(_("No output plugins available.\n\n"), stdout);
 		return;
 	}